diff --git a/Packages/vChewing_IMKUtils/Sources/IMKUtils/TISInputSourceExtension.swift b/Packages/vChewing_IMKUtils/Sources/IMKUtils/TISInputSourceExtension.swift
index 13ac234ed..d8ad4da68 100644
--- a/Packages/vChewing_IMKUtils/Sources/IMKUtils/TISInputSourceExtension.swift
+++ b/Packages/vChewing_IMKUtils/Sources/IMKUtils/TISInputSourceExtension.swift
@@ -97,6 +97,30 @@
       return true
     }
 
+    @discardableResult
+    public static func selectSystemABCInputSource() -> Bool {
+      // 1. Check if current ASCII capable keyboard input source is selectable, activated, and not vChewing.
+      if let currentASCII = TISCopyCurrentASCIICapableKeyboardInputSource()?.takeRetainedValue() {
+        if !currentASCII.identifier.lowercased().contains("vchewing"), currentASCII.isSelectable, currentASCII.isActivated {
+          return currentASCII.select()
+        }
+      }
+      // 2. Search for com.apple.keylayout.ABC among activated and selectable sources.
+      let allSources = rawTISInputSources(onlyASCII: true)
+      if let abcSource = allSources.first(where: { $0.identifier == "com.apple.keylayout.ABC" && $0.isSelectable && $0.isActivated }) {
+        return abcSource.select()
+      }
+      // 3. Fallback: Any selectable and activated ASCII layout that is not vChewing.
+      if let anyASCII = allSources.first(where: { !$0.identifier.lowercased().contains("vchewing") && $0.isSelectable && $0.isActivated }) {
+        return anyASCII.select()
+      }
+      // 4. Last resort: Any selectable ABC layout even if not marked activated yet.
+      if let abcSource = allSources.first(where: { $0.identifier == "com.apple.keylayout.ABC" && $0.isSelectable }) {
+        return abcSource.select()
+      }
+      return false
+    }
+
     @discardableResult
     public func deactivate() -> Bool {
       TISDisableInputSource(self) == noErr
diff --git a/Packages/vChewing_MainAssembly4Darwin/Sources/MainAssembly4Darwin/SessionHostWiring.swift b/Packages/vChewing_MainAssembly4Darwin/Sources/MainAssembly4Darwin/SessionHostWiring.swift
index a9064f0c7..fd433c19a 100644
--- a/Packages/vChewing_MainAssembly4Darwin/Sources/MainAssembly4Darwin/SessionHostWiring.swift
+++ b/Packages/vChewing_MainAssembly4Darwin/Sources/MainAssembly4Darwin/SessionHostWiring.swift
@@ -21,6 +21,7 @@ extension SessionHost {
     // IMEApp 動作依賴。
     host.isKeyboardJIS = { IMEApp.isKeyboardJIS }
     host.buzz = { IMEApp.buzz() }
+    host.switchToSystemABCInputSource = { TISInputSource.selectSystemABCInputSource() }
     // LMMgr 動作依賴。
     host.isCoreDBConnected = { LMMgr.isCoreDBConnected }
     host.syncLMPrefs = { LMMgr.syncLMPrefs() }
diff --git a/Packages/vChewing_MainAssembly4Darwin/Tests/MainAssembly4DarwinTests/MainAssemblyTests_Test5.swift b/Packages/vChewing_MainAssembly4Darwin/Tests/MainAssembly4DarwinTests/MainAssemblyTests_Test5.swift
index 218e7940a..02d5b73d8 100644
--- a/Packages/vChewing_MainAssembly4Darwin/Tests/MainAssembly4DarwinTests/MainAssemblyTests_Test5.swift
+++ b/Packages/vChewing_MainAssembly4Darwin/Tests/MainAssembly4DarwinTests/MainAssemblyTests_Test5.swift
@@ -237,4 +237,32 @@ extension MainAssemblyTests {
       #expect(testSession.isFuriousCopilotCandidateWindowVisible)
     }
   }
+
+  /// 測試連續錯誤自動切換至 ABC 後，重新切回唯音時自動恢復為中文模式。
+  @Test
+  func test508_ActivationAfterAutoSwitchToABC_ResetsASCIIModeToChinese() throws {
+    #expect(testSession.isActivated)
+    InputSession.current = testSession
+    defer {
+      InputSession.isAutoSwitchedToABC = false
+      testSession.isASCIIMode = false
+      InputSession.isASCIIModeForAllClients = false
+    }
+
+    // 模擬自動切換至 ABC 後的狀態：isASCIIMode == true, isAutoSwitchedToABC == true
+    testSession.isASCIIMode = true
+    InputSession.isAutoSwitchedToABC = true
+
+    #expect(testSession.isASCIIMode == true)
+    #expect(InputSession.isAutoSwitchedToABC == true)
+
+    // 模擬使用者切回唯音：呼叫 performServerActivation
+    testSession.performServerActivation()
+
+    // 驗證 isAutoSwitchedToABC 已被重置為 false，且 isASCIIMode 已自動恢復為 false（中文模式）
+    #expect(InputSession.isAutoSwitchedToABC == false)
+    #expect(testSession.isASCIIMode == false)
+    #expect(InputSession.isASCIIModeForAllClients == false)
+  }
 }
+
diff --git a/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsCocoa/VwrSettingsPaneCocoaGeneral.swift b/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsCocoa/VwrSettingsPaneCocoaGeneral.swift
index 4e5de54f0..2f1944155 100644
--- a/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsCocoa/VwrSettingsPaneCocoaGeneral.swift
+++ b/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsCocoa/VwrSettingsPaneCocoaGeneral.swift
@@ -64,6 +64,14 @@ extension SettingsPanesCocoa {
             fixWidth: contentWidth,
             prefUITab: .tabGeneral
           )
+          UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.renderCocoa(
+            fixWidth: contentWidth,
+            prefUITab: .tabGeneral
+          )
+          UserDef.kConsecutiveTypingErrorsThreshold.renderCocoa(
+            fixWidth: contentWidth,
+            prefUITab: .tabGeneral
+          )
           UserDef.kShowHanyuPinyinInCompositionBuffer.renderCocoa(
             fixWidth: contentWidth,
             prefUITab: .tabGeneral
diff --git a/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsUI/VwrSettingsPaneGeneral.swift b/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsUI/VwrSettingsPaneGeneral.swift
index e4ac44ef9..1d69261dd 100644
--- a/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsUI/VwrSettingsPaneGeneral.swift
+++ b/Packages/vChewing_SettingsUI/Sources/SettingsUI/SettingsUI/VwrSettingsPaneGeneral.swift
@@ -64,6 +64,8 @@ public struct VwrSettingsPaneGeneral: View {
           SpeechSputnik.shared.refreshStatus()
         }
         UserDef.kAutoCorrectReadingCombination.renderUI()
+        UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.renderUI()
+        UserDef.kConsecutiveTypingErrorsThreshold.renderUI()
         UserDef.kShowHanyuPinyinInCompositionBuffer.renderUI()
         UserDef.kKeepReadingUponCompositionError.renderUI()
         UserDef.kClassicHaninKeyboardSymbolModeShortcutEnabled.renderUI()
diff --git a/Packages/vChewing_Shared/Sources/Shared/PrefMgr_Core.swift b/Packages/vChewing_Shared/Sources/Shared/PrefMgr_Core.swift
index cad3b3f0f..b2c6ddff7 100644
--- a/Packages/vChewing_Shared/Sources/Shared/PrefMgr_Core.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/PrefMgr_Core.swift
@@ -168,6 +168,12 @@ public final class PrefMgr: PrefMgrProtocol, Sendable {
   @AppProperty(userDef: .kAutoCorrectReadingCombination)
   public var autoCorrectReadingCombination: Bool
 
+  @AppProperty(userDef: .kAutoSwitchToAlphanumericalOnConsecutiveErrors)
+  public var autoSwitchToAlphanumericalOnConsecutiveErrors: Bool
+
+  @AppProperty(userDef: .kConsecutiveTypingErrorsThreshold)
+  public var consecutiveTypingErrorsThreshold: Int
+
   @AppProperty(userDef: .kAlsoConfirmAssociatedCandidatesByEnter)
   public var alsoConfirmAssociatedCandidatesByEnter: Bool
 
diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
index e95c92204..711b11c4b 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/PrefMgrProtocol.swift
@@ -54,6 +54,8 @@ public protocol PrefMgrProtocol {
   var reducePOMLifetimeToNoMoreThan12Hours: Bool { get set }
   var useFixedCandidateOrderOnSelection: Bool { get set }
   var autoCorrectReadingCombination: Bool { get set }
+  var autoSwitchToAlphanumericalOnConsecutiveErrors: Bool { get set }
+  var consecutiveTypingErrorsThreshold: Int { get set }
   var readingNarrationCoverage: Int { get set }
   var alsoConfirmAssociatedCandidatesByEnter: Bool { get set }
   var keepReadingUponCompositionError: Bool { get set }
diff --git a/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
index c89988b98..454debd8e 100644
--- a/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/UserDef/UserDef.swift
@@ -80,6 +80,8 @@ nonisolated public enum UserDef: String, CaseIterable, Identifiable, Sendable {
   case kFetchSuggestionsFromPerceptionOverrideModel = "FetchSuggestionsFromPerceptionOverrideModel"
   case kUseFixedCandidateOrderOnSelection = "UseFixedCandidateOrderOnSelection"
   case kAutoCorrectReadingCombination = "AutoCorrectReadingCombination"
+  case kAutoSwitchToAlphanumericalOnConsecutiveErrors = "AutoSwitchToAlphanumericalOnConsecutiveErrors"
+  case kConsecutiveTypingErrorsThreshold = "ConsecutiveTypingErrorsThreshold"
   case kReadingNarrationCoverage = "ReadingNarrationCoverage"
   case kAlsoConfirmAssociatedCandidatesByEnter = "AlsoConfirmAssociatedCandidatesByEnter"
   case kKeepReadingUponCompositionError = "KeepReadingUponCompositionError"
@@ -374,6 +376,7 @@ nonisolated extension UserDef {
     case .kSpecifyIntonationKeyBehavior: 0 ... 2
     case .kSpecifyShiftBackSpaceKeyBehavior: 0 ... 2
     case .kUpperCaseLetterKeyBehavior: 0 ... 4
+    case .kConsecutiveTypingErrorsThreshold: 3 ... 8
     case .kReadingNarrationCoverage: 0 ... 2
     case .kRomanNumeralOutputFormat: 0 ... 3
     case .kSpecifyCmdOptCtrlEnterBehavior: 0 ... 4
@@ -497,6 +500,8 @@ nonisolated extension UserDef {
     case .kFetchSuggestionsFromPerceptionOverrideModel: return .bool(true)
     case .kUseFixedCandidateOrderOnSelection: return .bool(false)
     case .kAutoCorrectReadingCombination: return .bool(true)
+    case .kAutoSwitchToAlphanumericalOnConsecutiveErrors: return .bool(true)
+    case .kConsecutiveTypingErrorsThreshold: return .integer(5)
     case .kReadingNarrationCoverage: return .integer(0)
     case .kAlsoConfirmAssociatedCandidatesByEnter: return .bool(false)
     case .kKeepReadingUponCompositionError: return .bool(false)
@@ -898,6 +903,22 @@ nonisolated extension UserDef {
         shortTitle: "i18n:UserDef.kAutoCorrectReadingCombination.shortTitle",
         description: "i18n:UserDef.kAutoCorrectReadingCombination.description"
       )
+    case .kAutoSwitchToAlphanumericalOnConsecutiveErrors: return .init(
+        userDef: self,
+        shortTitle: "i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.shortTitle",
+        description: "i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.description"
+      )
+    case .kConsecutiveTypingErrorsThreshold: return .init(
+        userDef: self,
+        shortTitle: "i18n:UserDef.kConsecutiveTypingErrorsThreshold.shortTitle",
+        description: "i18n:UserDef.kConsecutiveTypingErrorsThreshold.description",
+        options: {
+          var result = [Int: String]()
+          guard let validNumeralValueRange else { return nil }
+          validNumeralValueRange.forEach { result[$0] = $0.description }
+          return result.isEmpty ? nil : result
+        }()
+      )
     case .kReadingNarrationCoverage: return .init(
         userDef: self, shortTitle: "i18n:UserDef.kReadingNarrationCoverage.shortTitle",
         description: "i18n:UserDef.kReadingNarrationCoverage.description",
diff --git a/Packages/vChewing_Tekkon/Sources/Tekkon/Tekkon_Constants.swift b/Packages/vChewing_Tekkon/Sources/Tekkon/Tekkon_Constants.swift
index 55bd899ad..9b7dd6ab1 100644
--- a/Packages/vChewing_Tekkon/Sources/Tekkon/Tekkon_Constants.swift
+++ b/Packages/vChewing_Tekkon/Sources/Tekkon/Tekkon_Constants.swift
@@ -32,6 +32,16 @@ public enum Tekkon {
     allowedConsonants + allowedSemivowels + allowedVowels + allowedIntonations
   }
 
+  /// 所有合法的國語注音音節與合法前綴（不含聲調）集合。
+  public static let allValidMandarinSyllables: Set<String> = {
+    var set = Set<String>()
+    for (phona, _) in arrPhonaToHanyuPinyin {
+      if [" ", "ˊ", "ˇ", "ˋ", "˙"].contains(phona) { continue }
+      set.insert(phona)
+    }
+    return set
+  }()
+
   // MARK: Internal
 
   /// 原始轉換對照表資料貯存專用佇列（數字標調格式）。
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler.swift
index 26c447478..1a47a29ca 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler.swift
@@ -76,6 +76,8 @@ public final class InputHandler: @MainActor InputHandlerProtocol {
   public var strCodePointBuffer = "" // 內碼輸入專用組碼區
   public var calligrapher = "" // 磁帶專用組筆區
   public var mixedAlphanumericalBuffer = "" // 混輸暫存 ASCII 緩衝區
+  public var consecutiveTypingErrors = [String]() // 連續輸入錯誤鍵暫存區
+  public var inFlightComposerKeys = [String]() // 當前注拼槽對應的鍵入字元暫存區
   public var furiousTrail = [String]() // 狂拼模式：自動 chop 提交鍵對應的拼音字母 blob trail
   public var furiousHighlightOverride: CandidateInState? // 狂拼 copilot 窗高亮候選（當拍消費）
   public var furiousCoSegmentedOffers = [FuriousCoSegmentedOffer]() // 狂拼 copilot 窗聯合重切（P164）的替代切分 offers
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_CoreProtocol.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_CoreProtocol.swift
index f9f4b856b..af6f3e8dd 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_CoreProtocol.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_CoreProtocol.swift
@@ -7,6 +7,7 @@
 // requirements defined in MIT License.
 
 import Foundation
+import Shared
 
 // MARK: - InputHandlerProtocol
 
@@ -52,6 +53,8 @@ public protocol InputHandlerProtocol: AnyObject {
   var strCodePointBuffer: String { get set } // 內碼輸入專用組碼區
   var calligrapher: String { get set } // 磁帶專用組筆區
   var mixedAlphanumericalBuffer: String { get set } // 混輸暫存 ASCII 緩衝區
+  var consecutiveTypingErrors: [String] { get set } // 連續輸入錯誤鍵暫存區
+  var inFlightComposerKeys: [String] { get set } // 當前注拼槽對應的鍵入字元暫存區
   var furiousTrail: [String] { get set } // 狂拼模式：自動 chop／空格固化提交鍵對應的拼音字母 blob trail
   var furiousHighlightOverride: CandidateInState? { get set } // 狂拼 copilot 窗高亮候選（當拍消費）
   var furiousCoSegmentedOffers: [FuriousCoSegmentedOffer] { get set
@@ -431,6 +434,8 @@ extension InputHandlerProtocol {
   public func clearComposerAndCalligrapher() {
     calligrapher.removeAll()
     composer.clear()
+    consecutiveTypingErrors.removeAll()
+    inFlightComposerKeys.removeAll()
     mixedAlphanumericalBuffer.removeAll()
     strCodePointBuffer.removeAll()
   }
@@ -1057,3 +1062,235 @@ extension InputHandlerProtocol {
     return textToCommit
   }
 }
+
+// MARK: - 連續錯誤鍵自動切換英數模式（Auto-switch to Alphanumerical on Consecutive Errors）
+
+extension InputHandlerProtocol {
+  /// 檢查給定按鍵是否屬於注音結構破壞鍵／無效鍵。
+  public func isConsideredPhoneticErrorKey(
+    input: some InputSignalProtocol,
+    inputText: String
+  ) -> Bool {
+    guard !composer.isPinyinMode else { return false }
+    if input.isCommandHeld || input.isControlHeld || input.isOptionHeld {
+      return false
+    }
+
+    // 1. 若該按鍵甚至不在當前鍵盤排列當中，直接判定為錯誤鍵。
+    if !composer.inputValidityCheck(charStr: inputText) {
+      return true
+    }
+
+    // 2. 以副本試驗該按鍵的吸收狀況。
+    var trialComposer = composer
+    let consumed = trialComposer.receiveKey(fromString: inputText)
+    if !consumed || trialComposer.value == composer.value {
+      return true
+    }
+
+    // 2a. 首音調判定：若當前注拼槽為空，且按鍵為聲調，但未開啟前置聲調設定，判定為錯誤鍵。
+    if composer.isEmpty {
+      if !trialComposer.intonation.isEmpty && !prefs.acceptLeadingIntonations {
+        return true
+      }
+      return false
+    }
+
+    // 2b. 試驗吸收後的聲介韻組合是否在國語注音合法音節集合內。
+    // 若注拼槽已有音位，且追加此鍵後的聲介韻組合不屬於任何合法音節或合法音節前綴，直接判定為錯誤鍵。
+    let trialZhuyin = trialComposer.consonant.value + trialComposer.semivowel.value + trialComposer.vowel.value
+    if !trialZhuyin.isEmpty && !Tekkon.allValidMandarinSyllables.contains(trialZhuyin) {
+      return true
+    }
+
+    // 2c. 覆寫既有位置判定：
+    // 聲母後重複輸入聲母
+    if !composer.consonant.isEmpty, !trialComposer.consonant.isEmpty,
+       composer.consonant != trialComposer.consonant {
+      return true
+    }
+    // 介母後重複輸入介母
+    if !composer.semivowel.isEmpty, !trialComposer.semivowel.isEmpty,
+       composer.semivowel != trialComposer.semivowel {
+      return true
+    }
+    // 韻母後重複輸入韻母
+    if !composer.vowel.isEmpty, !trialComposer.vowel.isEmpty,
+       composer.vowel != trialComposer.vowel {
+      return true
+    }
+    // 聲調後重複輸入聲調
+    if !composer.intonation.isEmpty, !trialComposer.intonation.isEmpty,
+       composer.intonation != trialComposer.intonation {
+      return true
+    }
+
+    // 2d. 聲/介/韻/調 槽位順序違反判定：
+    // 韻母後輸入聲母
+    if !composer.vowel.isEmpty, trialComposer.consonant != composer.consonant {
+      return true
+    }
+    // 韻母後輸入介母
+    if !composer.vowel.isEmpty, trialComposer.semivowel != composer.semivowel {
+      return true
+    }
+    // 介母後輸入聲母
+    if !composer.semivowel.isEmpty, trialComposer.consonant != composer.consonant {
+      return true
+    }
+    // 聲調後輸入聲/介/韻
+    if !composer.intonation.isEmpty,
+       trialComposer.consonant != composer.consonant
+       || trialComposer.semivowel != composer.semivowel
+       || trialComposer.vowel != composer.vowel {
+      return true
+    }
+
+    // 2e. 破壞既有已鍵入音位判定（例如自動糾錯移除掉已有的介母、韻母或聲母）：
+    if !composer.semivowel.isEmpty, trialComposer.semivowel.isEmpty {
+      return true
+    }
+    if !composer.vowel.isEmpty, trialComposer.vowel.isEmpty {
+      return true
+    }
+    if !composer.consonant.isEmpty, trialComposer.consonant.isEmpty {
+      return true
+    }
+
+    return false
+  }
+
+  /// 檢查是否需要因「連續鍵入 5 個錯誤鍵」而自動切換至英數模式。
+  public func handleConsecutiveTypingErrorsSwitchIfNeeded(
+    input: some InputSignalProtocol
+  ) -> Bool? {
+    guard prefs.autoSwitchToAlphanumericalOnConsecutiveErrors,
+          let session = session,
+          session.inputMode == .imeModeCHT,
+          !session.isASCIIMode,
+          !composer.isPinyinMode,
+          !prefs.mixedAlphanumericalEnabled,
+          currentTypingMethod == .vChewingFactory,
+          !input.isCommandHeld, !input.isControlHeld, !input.isOptionHeld,
+          !input.isEnter, !input.isTab, !input.isEsc,
+          !input.isBackSpace, !input.isDelete,
+          !input.isCursorBackward, !input.isCursorForward,
+          !input.isUp, !input.isDown, !input.isLeft, !input.isRight,
+          !input.isPageUp, !input.isPageDown, !input.isHome, !input.isEnd
+    else {
+      if input.isEnter || input.isTab || input.isEsc || input.isBackSpace || input.isDelete
+        || input.isCursorBackward || input.isCursorForward || input.isUp || input.isDown
+        || input.isLeft || input.isRight || input.isPageUp || input.isPageDown || input.isHome || input.isEnd
+      {
+        consecutiveTypingErrors.removeAll()
+        inFlightComposerKeys.removeAll()
+      }
+      return nil
+    }
+
+    if let keyCodeType = KeyCode(rawValue: input.keyCode) {
+      switch keyCodeType {
+      case .kSymbolMenuPhysicalKeyIntl, .kSymbolMenuPhysicalKeyJIS, .kContextMenu:
+        consecutiveTypingErrors.removeAll()
+        inFlightComposerKeys.removeAll()
+        return nil
+      default: break
+      }
+    }
+
+    let threshold = max(3, prefs.consecutiveTypingErrorsThreshold)
+
+    // 當已處於連續錯誤狀態（已累積 >= 2 個錯誤鍵）時，Space 被視為英數輸入的一環（如 "cd .."、"ls -la"、"git status"），
+    // 應計入連續鍵擊並阻斷注音一聲/送字；若未處於錯誤狀態，Space 仍為正常的注音一聲或送字。
+    if input.isSpace {
+      if consecutiveTypingErrors.count >= 2 {
+        consecutiveTypingErrors.append(" ")
+        composer.clear()
+        calligrapher.removeAll()
+        inFlightComposerKeys.removeAll()
+        if consecutiveTypingErrors.count >= threshold {
+          return commitConsecutiveErrorsAndSwitchToABC(session: session)
+        }
+        return true
+      } else {
+        consecutiveTypingErrors.removeAll()
+        inFlightComposerKeys.removeAll()
+        return nil
+      }
+    }
+
+    var inputText = (input.inputTextIgnoringModifiers ?? input.text)
+    inputText = inputText.lowercased().applyingTransformFW2HW(reverse: false)
+    let charToRecord = input.text.isEmpty ? inputText : input.text
+
+    // 當已處於連續錯誤狀態（已累積 >= 2 個鍵）時，後續無論是字母、標點符號或數字，
+    // 皆視為正在輸入英數字串（如 "cd .." 中的 "." 與 "/"、"git log" 中的字母），持續累積直到滿門檻自動切換。
+    if consecutiveTypingErrors.count >= 2 {
+      consecutiveTypingErrors.append(charToRecord)
+      composer.clear()
+      calligrapher.removeAll()
+      inFlightComposerKeys.removeAll()
+      if consecutiveTypingErrors.count >= threshold {
+        return commitConsecutiveErrorsAndSwitchToABC(session: session)
+      }
+      return true
+    }
+
+    // 若尚未處於錯誤狀態（累積小於 2 個鍵），且該鍵是合法標點符號按鍵（詞庫中有定義標點符號），
+    // 則視為正常的中文標點輸入，不判定為錯誤。
+    if let puncKeys = punctuationQueryStrings(input: input),
+       puncKeys.contains(where: { currentLM.hasUnigramsFor(keyArray: [$0]) })
+    {
+      consecutiveTypingErrors.removeAll()
+      inFlightComposerKeys.removeAll()
+      return nil
+    }
+
+    let isError = isConsideredPhoneticErrorKey(input: input, inputText: inputText)
+
+    if isError {
+      // 若在累積錯誤鍵之前注拼槽內已有尚未固化／提交的鍵入字元（如合法的聲母或介母，但因後續鍵入破壞注音結構而判定為英文打字），
+      // 將這些尚未成為完整漢字的按鍵一併作為錯誤鍵序列納入
+      if !inFlightComposerKeys.isEmpty {
+        consecutiveTypingErrors = inFlightComposerKeys + [charToRecord]
+        inFlightComposerKeys.removeAll()
+      } else {
+        consecutiveTypingErrors.append(charToRecord)
+      }
+      composer.clear()
+      calligrapher.removeAll()
+      if consecutiveTypingErrors.count >= threshold {
+        return commitConsecutiveErrorsAndSwitchToABC(session: session)
+      }
+      return true
+    } else {
+      if composer.isEmpty {
+        inFlightComposerKeys = [charToRecord]
+        consecutiveTypingErrors = [charToRecord]
+      } else {
+        inFlightComposerKeys.append(charToRecord)
+      }
+    }
+    return nil
+  }
+
+  @discardableResult
+  private func commitConsecutiveErrorsAndSwitchToABC(session: Session) -> Bool {
+    let textToCommit = consecutiveTypingErrors.joined()
+    consecutiveTypingErrors.removeAll()
+    inFlightComposerKeys.removeAll()
+    composer.clear()
+    calligrapher.removeAll()
+    assembler.clear()
+    session.switchState(State.ofCommitting(textToCommit: textToCommit))
+    let switched = SessionHost.shared.switchToSystemABCInputSource()
+    if switched {
+      session.isPassThroughUntilDeactivated = true
+      session.passThroughUntilDeactivatedTimestamp = Date()
+      InputSession.isAutoSwitchedToABC = true
+    } else {
+      session.isASCIIMode = true
+    }
+    return true
+  }
+}
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_HandleComposition.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_HandleComposition.swift
index 918ac9a0a..0c944ecb5 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_HandleComposition.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_HandleComposition.swift
@@ -32,6 +32,9 @@ extension InputHandlerProtocol {
       case .cassette:
         return CassetteTypewriter(self).handle(input)
       case .bopomofoKeyblock:
+        if let handled = handleConsecutiveTypingErrorsSwitchIfNeeded(input: input) {
+          return handled
+        }
         if prefs.mixedAlphanumericalEnabled {
           return MixedAlphanumericalTypewriter(self).handle(input)
         }
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_TriageInput.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_TriageInput.swift
index 9cc49f232..8e2fd9d43 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_TriageInput.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/InputHandler/InputHandler_TriageInput.swift
@@ -9,11 +9,21 @@
 /// 該檔案乃輸入調度模組當中「用來規定當 IMK 接受按鍵訊號時且首次交給輸入調度模組處理時、
 /// 輸入調度模組要率先處理」的部分。據此判斷是否需要將按鍵處理委派給其它成員函式。
 
+import Foundation
+
 // MARK: - § 根據狀態調度按鍵輸入 (Handle Input with States) * Triage
 
 extension InputHandlerProtocol {
   public func triageInput(event input: InputSignalProtocol) -> Bool {
     guard let session = session else { return false }
+    if session.isPassThroughUntilDeactivated {
+      if let timestamp = session.passThroughUntilDeactivatedTimestamp,
+         Date().timeIntervalSince(timestamp) < 2.0 {
+        return false
+      }
+      session.isPassThroughUntilDeactivated = false
+      session.passThroughUntilDeactivatedTimestamp = nil
+    }
     var state: State { session.state }
     currentLM.syncPrefs()
 
@@ -48,6 +58,14 @@ extension InputHandlerProtocol {
     func triageByKeyCode() -> Bool? {
       guard let keyCodeType = KeyCode(rawValue: input.keyCode) else { return nil }
       switch keyCodeType {
+      case .kEscape, .kContextMenu, .kTab, .kDownArrow, .kLeftArrow, .kRightArrow, .kUpArrow,
+           .kHome, .kEnd, .kBackSpace, .kWindowsDelete, .kCarriageReturn, .kLineFeed,
+           .kSymbolMenuPhysicalKeyIntl, .kSymbolMenuPhysicalKeyJIS:
+        consecutiveTypingErrors.removeAll()
+        inFlightComposerKeys.removeAll()
+      default: break
+      }
+      switch keyCodeType {
       case .kEscape: return handleEsc()
       case .kContextMenu, .kTab:
         if input.isTab, hasFuriousFrontPending {
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/InputSession.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/InputSession.swift
index 2abe7a414..b443b9c51 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/InputSession.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/InputSession.swift
@@ -53,6 +53,10 @@ public final class InputSession: @MainActor SessionProtocol, Sendable {
   public static var isASCIIModeForAllClients = false
   /// 一個共用辭典，專門用來給每個副本用的 isASCIIMode 追蹤用餐數。
   public static var isASCIIModeForEachClient: [String: Bool] = [:]
+  /// 記錄是否剛因連續鍵入錯誤而自動切換至 ABC 輸入法。
+  /// 若為 true，則當下次本輸入法被重新啟用（performServerActivation）時，
+  /// 應自動將英數模式解除，回到中文輸入模式。
+  public static var isAutoSwitchedToABC = false
 
   // MARK: - 極性雙緩衝 Session 池
 
@@ -79,6 +83,9 @@ public final class InputSession: @MainActor SessionProtocol, Sendable {
 
   public let id: UUID = .init()
 
+  public var isPassThroughUntilDeactivated: Bool = false
+  public var passThroughUntilDeactivatedTimestamp: Date? = nil
+
   public var clientProxyObjectIdentifier: ObjectIdentifier?
 
   public var buzzer: (() -> ())? = { mainSync { SessionHost.shared.buzz() } }
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionCoreProtocol.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionCoreProtocol.swift
index 511f6a424..44b9a36cf 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionCoreProtocol.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionCoreProtocol.swift
@@ -31,7 +31,11 @@ public protocol SessionCoreProtocol: AnyObject & CtlCandidateDelegate {
   var id: UUID { get }
   /// 用以記錄當前輸入法狀態的變數。(有 DidSet)
   var state: IMEState { get set }
-  var isASCIIMode: Bool { get }
+  var isASCIIMode: Bool { get set }
+  /// 記錄是否剛觸發連續錯誤自動切換至 ABC，此時在 deactivateServer 前應將後續按鍵 pass-through 給系統。
+  var isPassThroughUntilDeactivated: Bool { get set }
+  var passThroughUntilDeactivatedTimestamp: Date? { get set }
+  var inputMode: Shared.InputMode { get }
   var clientMitigationLevel: Int { get }
   var ui: SessionUIProtocol? { get }
 
@@ -156,6 +160,10 @@ extension SessionCoreProtocol {
 // MARK: - Convenience Overloads
 
 extension SessionCoreProtocol {
+  public var inputMode: Shared.InputMode {
+    IMEApp.currentInputMode
+  }
+
   public var isCurrentSession: Bool {
     id == ui?.currentSessionID
   }
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionHost.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionHost.swift
index 6d93377a5..c03a19eac 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionHost.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionHost.swift
@@ -32,6 +32,8 @@ public final class SessionHost {
   public var isKeyboardJIS: () -> Bool = { false }
   /// 蜂鳴或放屁聲。
   public var buzz: () -> () = {}
+  /// 切換至系統 ABC 輸入法（外部鍵盤輸入來源）。
+  public var switchToSystemABCInputSource: () -> Bool = { false }
 
   // MARK: - LMMgr 動作依賴
 
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionProtocol.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionProtocol.swift
index ade70a378..46962464c 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionProtocol.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/Session/SessionProtocol.swift
@@ -38,6 +38,8 @@ public protocol SessionProtocol: AnyObject, CtlCandidateDelegate,
   static var isASCIIModeForAllClients: Bool { get set }
   /// 一個共用辭典，專門用來給每個副本用的 isASCIIMode 追蹤用餐數。
   static var isASCIIModeForEachClient: [String: Bool] { get set }
+  /// 記錄是否剛因連續鍵入錯誤而自動切換至 ABC 輸入法。
+  static var isAutoSwitchedToABC: Bool { get set }
   /// 偏好設定。
   var prefs: PrefMgrProtocol { get set }
   /// 上一個被處理過的鍵盤事件。
@@ -191,6 +193,8 @@ extension SessionProtocol {
   }
 
   public func performServerDeactivation() {
+    isPassThroughUntilDeactivated = false
+    passThroughUntilDeactivatedTimestamp = nil
     guard Self.current?.id != id else { return }
     isActivated = false
     // `resetInputHandler()` 會自動搞定 Empty 狀態。
@@ -210,6 +214,17 @@ extension SessionProtocol {
   }
 
   public func performServerActivation() {
+    isPassThroughUntilDeactivated = false
+    passThroughUntilDeactivatedTimestamp = nil
+    // 檢查若前次是因連續鍵入錯誤而自動切換至 ABC，在使用者重新切回唯音時應自動恢復為中文模式。
+    if Self.isAutoSwitchedToABC {
+      Self.isAutoSwitchedToABC = false
+      isASCIIMode = false
+      Self.isASCIIModeForAllClients = false
+      isASCIIModeForThisClient = false
+      Self.isASCIIModeForEachClient.removeAll()
+    }
+
     // MARK: 快速路徑 — 最佳化 CapsLock 中英頻繁切換的場景。
 
     /// 每次 activateServer 都是一次全新的啟用事件，
@@ -225,6 +240,9 @@ extension SessionProtocol {
         inputMode = resolvedInputMode
       }
       state = .ofEmpty()
+      if isASCIIMode, !SessionHost.shared.isKeyboardJIS() {
+        isASCIIMode = false
+      }
       lastAppliedKeyboardLayout = nil
       setKeyLayout()
       return
diff --git a/Packages/vChewing_Typewriter/Sources/Typewriter/Typewriter/Typewriter_BPMFFullMatch.swift b/Packages/vChewing_Typewriter/Sources/Typewriter/Typewriter/Typewriter_BPMFFullMatch.swift
index dbfeb5256..48456fd77 100644
--- a/Packages/vChewing_Typewriter/Sources/Typewriter/Typewriter/Typewriter_BPMFFullMatch.swift
+++ b/Packages/vChewing_Typewriter/Sources/Typewriter/Typewriter/Typewriter_BPMFFullMatch.swift
@@ -324,6 +324,8 @@ public struct BPMFFullMatchTypewriter<Handler: InputHandlerProtocol>: Typewriter
       }
 
       handler.composer.clear()
+      handler.consecutiveTypingErrors.removeAll()
+      handler.inFlightComposerKeys.removeAll()
       switch handler.assembler.isEmpty {
       case false: session.switchState(handler.generateStateOfInputting())
       case true: session.switchState(State.ofAbortion())
@@ -354,6 +356,8 @@ public struct BPMFFullMatchTypewriter<Handler: InputHandlerProtocol>: Typewriter
     let textToCommit = handler.commitOverflownComposition
     handler.retrievePOMSuggestions(apply: true)
     handler.composer.clear()
+    handler.consecutiveTypingErrors.removeAll()
+    handler.inFlightComposerKeys.removeAll()
 
     var inputting = handler.generateStateOfInputting()
     inputting.textToCommit = textToCommit
diff --git a/Packages/vChewing_Typewriter/Tests/TypewriterTests/InputHandlerTests_AutoSwitchOnErrors.swift b/Packages/vChewing_Typewriter/Tests/TypewriterTests/InputHandlerTests_AutoSwitchOnErrors.swift
new file mode 100644
index 000000000..233fb40b0
--- /dev/null
+++ b/Packages/vChewing_Typewriter/Tests/TypewriterTests/InputHandlerTests_AutoSwitchOnErrors.swift
@@ -0,0 +1,534 @@
+// (c) 2021 and onwards The vChewing Project (MIT-NTL License).
+// ====================
+// This code is released under the MIT license (SPDX-License-Identifier: MIT)
+// ... with NTL restriction stating that:
+// No trademark license is granted to use the trade names, trademarks, service
+// marks, or product names of Contributor, except as required to fulfill notice
+// requirements defined in MIT License.
+
+import Foundation
+import Homa
+import LangModelAssembly
+import Shared
+import Tekkon
+import Testing
+@testable import Typewriter
+
+// MARK: - AutoSwitchOnConsecutiveErrors Tests
+
+extension InputHandlerTests {
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_BasicSwitchToABC() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+      InputSession.isAutoSwitchedToABC = false
+    }
+
+    // Dachen: g=ㄕ, r=ㄐ, e=ㄍ, a=ㄇ, t=ㄔ (5 consonants -> 5 consecutive errors)
+    typeSentence("great")
+
+    #expect(testSession.recentCommissions == ["great"])
+    #expect(switchedToABC == true)
+    #expect(InputSession.isAutoSwitchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_CdDotDotSlash() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+      InputSession.isAutoSwitchedToABC = false
+    }
+
+    // 當輸入到第 5 鍵（即 "cd .." 中的第二個 "."）時，累計達到 5 個錯誤鍵，
+    // 即刻觸發自動切換至系統 ABC 輸入法，並將已鍵入的 5 個英數字元 "cd .." 遞交。
+    // 同時標記 isPassThroughUntilDeactivated == true，確保尚未切離此 session 的後續按鍵（如第 6 鍵 "/"）
+    // 不會被唯音當成注音（大千鍵盤的 "ㄥ"）攔截，而是直接 pass-through 由 OS 送出。
+    // 唯音自身的 isASCIIMode 仍保持 false（中文模式），以確保切回唯音時能直接輸入中文。
+    typeSentence("cd ..")
+    #expect(switchedToABC == true)
+    #expect(InputSession.isAutoSwitchedToABC == true)
+    #expect(testSession.recentCommissions == ["cd .."])
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+
+    // 第 6 鍵 "/" 在 pass-through 模式下直接由系統處理，不被唯音攔截為注音 "ㄥ"
+    let slashHandled = testHandler.triageInput(event: KBEvent.KeyEventData(chars: "/").asEvent)
+    #expect(!slashHandled)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_GitLog() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    for ch in "git log" {
+      _ = testHandler.triageInput(event: KBEvent.KeyEventData(chars: String(ch)).asEvent)
+    }
+    #expect(switchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions == ["git l"])
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+
+    // 後續按鍵在 pass-through 模式下直接交由 OS 送出
+    let oHandled = testHandler.triageInput(event: KBEvent.KeyEventData(chars: "o").asEvent)
+    #expect(!oHandled)
+    let gHandled = testHandler.triageInput(event: KBEvent.KeyEventData(chars: "g").asEvent)
+    #expect(!gHandled)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_LeftBracketInputsFullWidthBracket() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    let leftBracketEvent = KBEvent.KeyEventData(chars: "[", keyCode: 33).asEvent
+    let leftHandled = testHandler.triageInput(event: leftBracketEvent)
+    #expect(leftHandled == true)
+    #expect(testHandler.assembler.assembledSentence.values.joined() == "「")
+
+    let rightBracketEvent = KBEvent.KeyEventData(chars: "]", keyCode: 30).asEvent
+    let rightHandled = testHandler.triageInput(event: rightBracketEvent)
+    #expect(rightHandled == true)
+    #expect(testHandler.assembler.assembledSentence.values.joined() == "「」")
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_SudoApt() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    // "sudo " 剛好滿 5 個鍵，即使 "su" 在大千上是合法的 "ㄋㄧ"，
+    // 當鍵入第三鍵 "d"（ㄎ）時因破壞注音結構而判定為英文打字，前序字元 "su" 一併納入錯誤序列；
+    // 鍵入到第 5 鍵空格時即觸發切換至 ABC 並遞交 "sudo "。
+    typeSentence("sudo ")
+    #expect(switchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions == ["sudo "])
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_NormalChineseTypingUntouched() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    // 正常輸入注音："su3" -> "你" (3聲)
+    typeSentence("su3")
+    #expect(!switchedToABC)
+    #expect(!testSession.isASCIIMode)
+    #expect(testHandler.consecutiveTypingErrors.isEmpty)
+    #expect(testHandler.inFlightComposerKeys.isEmpty)
+    #expect(testHandler.assembler.assembledSentence.values.joined() == "你")
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_CdDotDotSlashFallbackToASCII() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    SessionHost.shared.switchToSystemABCInputSource = { false }
+
+    // 當切換系統 ABC 輸入法不可用時，降級啟用 session.isASCIIMode = true。
+    // 第 5 鍵 "cd .." 觸發遞交並轉為英數模式，後續的第 6 鍵 "/" 即在英數模式下 pass-through 直接交由 OS 送出。
+    typeSentence("cd ..")
+    #expect(testSession.isASCIIMode == true)
+    #expect(testSession.recentCommissions == ["cd .."])
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+
+    // 第 6 鍵 "/" 在英數模式下 pass-through 直接由系統處理
+    let slashHandled = testHandler.triageInput(event: KBEvent.KeyEventData(chars: "/").asEvent)
+    #expect(!slashHandled)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_FallbackToASCIIModeWhenABCUnavailable() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    SessionHost.shared.switchToSystemABCInputSource = { false }
+
+    // Dachen: g=ㄕ, r=ㄐ, e=ㄍ, a=ㄇ, t=ㄔ (5 consonants -> 5 consecutive errors)
+    typeSentence("great")
+
+    #expect(testSession.recentCommissions == ["great"])
+    #expect(testSession.isASCIIMode == true)
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+
+    // Subsequent input in ASCII mode should return false (pass-through to OS)
+    let nextEvent = KBEvent.KeyEventData(chars: "s").asEvent
+    let handled = testHandler.triageInput(event: nextEvent)
+    #expect(!handled)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_PriorAssemblerContentDiscarded() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    // Type a valid Chinese syllable first: ㄧㄡ ("u. ") -> forms a node in assembler
+    typeSentence("u. ")
+    #expect(!testHandler.assembler.isEmpty)
+
+    // Now type 5 consecutive error keys: "great"
+    typeSentence("great")
+
+    // The prior assembled sentence must be discarded, only "great" committed
+    #expect(testSession.recentCommissions.last == "great")
+    #expect(switchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testHandler.assembler.isEmpty)
+    #expect(testHandler.composer.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_NormalChineseTypingDoesNotTrigger() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    // Valid Chinese typing: ㄋㄧˇ ("su3") -> valid syllable
+    typeSentence("su3")
+    #expect(testSession.isASCIIMode == false)
+    #expect(testHandler.consecutiveTypingErrors.isEmpty)
+
+    // Followed by ㄏㄠˇ ("cl3") -> valid syllable
+    typeSentence("cl3")
+    #expect(testSession.isASCIIMode == false)
+    #expect(testHandler.consecutiveTypingErrors.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_BackSpaceClearsErrorBuffer() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    // Type 4 consecutive errors: "grea"
+    typeSentence("grea")
+    #expect(testHandler.consecutiveTypingErrors.count == 4)
+    #expect(testSession.isASCIIMode == false)
+
+    // Press BackSpace
+    _ = testHandler.triageInput(event: KBEvent.KeyEventData.backspace.asEvent)
+    #expect(testHandler.consecutiveTypingErrors.isEmpty)
+
+    // Type 2 more errors: "ts"
+    typeSentence("ts")
+    #expect(testHandler.consecutiveTypingErrors.count == 2)
+    #expect(testSession.isASCIIMode == false)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_DisabledPreference() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = false
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    typeSentence("great")
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_SimplifiedChineseModeIgnored() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHS
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    typeSentence("great")
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_PinyinModeIgnored() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+    testHandler.composer.ensureParser(arrange: .ofHanyuPinyin)
+
+    typeSentence("great")
+    #expect(testSession.isASCIIMode == false)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_MixedAlphanumericalIgnored() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testHandler.prefs.mixedAlphanumericalEnabled = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    typeSentence("great")
+    #expect(testSession.isASCIIMode == false)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_MkdirCommand() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    typeSentence("mkdir")
+
+    #expect(switchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions == ["mkdir"])
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+  }
+
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_CustomThreshold() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testHandler.prefs.consecutiveTypingErrorsThreshold = 3
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    var switchedToABC = false
+    SessionHost.shared.switchToSystemABCInputSource = {
+      switchedToABC = true
+      return true
+    }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+      testHandler.prefs.consecutiveTypingErrorsThreshold = 5
+    }
+
+    // "git" with threshold = 3 should trigger switch on 3 keys
+    typeSentence("git")
+
+    #expect(switchedToABC == true)
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+    #expect(testSession.recentCommissions == ["git"])
+    #expect(testHandler.composer.isEmpty)
+    #expect(testHandler.assembler.isEmpty)
+  }
+
+  /// 測試自動切換至 ABC 後，使用者重新切回唯音（performServerActivation）時，
+  /// 輸入法應已重置 pass-through 狀態並維持中文模式（isASCIIMode == false），
+  /// 且能立即正常鍵入中文。
+  @Test
+  func test_AutoSwitchOnConsecutiveErrors_SwitchBackToVChewingEnablesChineseImmediately() throws {
+    guard let testHandler, let testSession else {
+      Issue.record("Test handler or session is nil.")
+      return
+    }
+    testHandler.prefs.autoSwitchToAlphanumericalOnConsecutiveErrors = true
+    testSession.inputMode = .imeModeCHT
+    testSession.isASCIIMode = false
+    testSession.recentCommissions.removeAll()
+    testSession.resetInputHandler(forceComposerCleanup: true)
+
+    SessionHost.shared.switchToSystemABCInputSource = { true }
+    defer {
+      SessionHost.shared.switchToSystemABCInputSource = { false }
+    }
+
+    // 1. 打 "cd .." 觸發自動切換至 ABC
+    typeSentence("cd ..")
+    #expect(testSession.recentCommissions == ["cd .."])
+    #expect(testSession.isPassThroughUntilDeactivated == true)
+    #expect(testSession.isASCIIMode == false)
+
+    // 2. 隨後的 "/" 仍在 pass-through，不被攔截
+    let slashHandled = testHandler.triageInput(event: KBEvent.KeyEventData(chars: "/").asEvent)
+    #expect(!slashHandled)
+
+    // 3. 模擬使用者透過 Cmd+Space 切回唯音：呼叫 performServerActivation
+    testSession.performServerActivation()
+    #expect(testSession.isPassThroughUntilDeactivated == false)
+    #expect(testSession.isASCIIMode == false)
+
+    // 4. 切回唯音後，應立即能正常輸入中文，無須手動按 Shift 或再次切換
+    // 在大千鍵盤上打 "su3" -> "你" (3聲)
+    typeSentence("su3")
+    #expect(testHandler.assembler.assembledSentence.values.joined() == "你")
+  }
+}
diff --git a/Packages/vChewing_Typewriter/Tests/TypewriterTests/TestComponents/MockedInputHandlerAndStates.swift b/Packages/vChewing_Typewriter/Tests/TypewriterTests/TestComponents/MockedInputHandlerAndStates.swift
index 03753f0c7..e727d8a16 100644
--- a/Packages/vChewing_Typewriter/Tests/TypewriterTests/TestComponents/MockedInputHandlerAndStates.swift
+++ b/Packages/vChewing_Typewriter/Tests/TypewriterTests/TestComponents/MockedInputHandlerAndStates.swift
@@ -67,6 +67,8 @@ public final class MockInputHandler: @MainActor InputHandlerProtocol {
   public var strCodePointBuffer = ""
   public var calligrapher = ""
   public var mixedAlphanumericalBuffer = ""
+  public var consecutiveTypingErrors = [String]()
+  public var inFlightComposerKeys = [String]()
   public var furiousTrail = [String]() // 狂拼模式：自動 chop 提交鍵對應的拼音字母 blob trail
   public var furiousHighlightOverride: CandidateInState? // 狂拼 copilot 窗高亮候選（當拍消費）
   public var furiousCoSegmentedOffers = [FuriousCoSegmentedOffer]() // 狂拼 copilot 窗聯合重切（P164）的替代切分 offers
@@ -101,6 +103,9 @@ public final class MockSession: @MainActor SessionCoreProtocol {
   public var state: IMEState = .init()
   public var inputHandler: MockInputHandler?
   public var isASCIIMode: Bool = false
+  public var isPassThroughUntilDeactivated: Bool = false
+  public var passThroughUntilDeactivatedTimestamp: Date? = nil
+  public var inputMode: Shared.InputMode = .imeModeCHT
   public var clientMitigationLevel: Int = 0
   /// 預設為 nil（候選窗不存在）；測試需要模擬候選窗已顯示時才指派。
   public var mockCandidateController: MockCandidateController?
@@ -137,6 +142,15 @@ public final class MockSession: @MainActor SessionCoreProtocol {
     vCLog(logMessage)
   }
 
+  public func performServerActivation() {
+    isPassThroughUntilDeactivated = false
+    passThroughUntilDeactivatedTimestamp = nil
+    if isASCIIMode {
+      isASCIIMode = false
+    }
+    state = .ofEmpty()
+  }
+
   public func getCandidate(at index: Int) -> CandidateInState? {
     guard state.candidates.indices.contains(index) else { return nil }
     return state.candidates[index]
diff --git a/Sources/vChewingIME_macOS/Resources/en.lproj/Localizable.strings b/Sources/vChewingIME_macOS/Resources/en.lproj/Localizable.strings
index ea3c526e0..c5aff164f 100644
--- a/Sources/vChewingIME_macOS/Resources/en.lproj/Localizable.strings
+++ b/Sources/vChewingIME_macOS/Resources/en.lproj/Localizable.strings
@@ -345,6 +345,10 @@
 "i18n:UserDef.kAutoCompositeWithLongestPossibleCassetteKey.shortTitle" = "Auto-composite when the longest possible key is formed";
 "i18n:UserDef.kAutoCorrectReadingCombination.description" = "This feature is disabled with mixed Chinese-English typing fallback due to compatibility concerns.";
 "i18n:UserDef.kAutoCorrectReadingCombination.shortTitle" = "Automatically correct reading combinations when typing";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.description" = "Under Traditional Chinese typing mode, clear the composition buffer, commit corresponding alphanumeric text, and switch to the ABC input method if consecutive invalid phonetic keys reach the threshold.";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.shortTitle" = "Auto-switch to ABC input method upon consecutive typing errors";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.description" = "Number of consecutive phonetic error keystrokes before triggering auto-switch to ABC input method (default: 5, range: 3-8).";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.shortTitle" = "Consecutive typing errors threshold:";
 "i18n:UserDef.kBasicKeyboardLayout.description" = "Choose the macOS-level basic keyboard layout. Zhuyin typing and Pinyin typing are now mutually switchable modes: while typing Pinyin, this layout determines the actual characters produced by your keys, so non-QWERTY alphanumerical keyboard layouts apply as well; while typing Zhuyin, keystrokes are translated as if on a standard layout, and the on-screen keyboard is displayed accordingly.";
 "i18n:UserDef.kBasicKeyboardLayout.shortTitle" = "Basic Keyboard Layout:";
 "i18n:UserDef.kBeepSoundPreference.option.0" = "Muted";
diff --git a/Sources/vChewingIME_macOS/Resources/ja.lproj/Localizable.strings b/Sources/vChewingIME_macOS/Resources/ja.lproj/Localizable.strings
index 6599d7c5e..a349e780a 100644
--- a/Sources/vChewingIME_macOS/Resources/ja.lproj/Localizable.strings
+++ b/Sources/vChewingIME_macOS/Resources/ja.lproj/Localizable.strings
@@ -345,6 +345,10 @@
 "i18n:UserDef.kAutoCompositeWithLongestPossibleCassetteKey.shortTitle" = "最長可能キーができた場合、文字を組み立つ";
 "i18n:UserDef.kAutoCorrectReadingCombination.description" = "互換性のため、中英混在入力のフォールバックがONの場合、この機能は不作動。";
 "i18n:UserDef.kAutoCorrectReadingCombination.shortTitle" = "入力中で打ち間違った発音組み合わせを自動的に訂正する";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.description" = "繁体字中国語入力モード時、注音構造に合致しない誤入力が指定回数連続した場合、未確定文字列を破棄して英数字を出力し、ABC入力ソースへ自動切替します。";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.shortTitle" = "タイピング誤入力が閾値連続した際にABC入力ソースへ自動切替";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.description" = "英数・ABC入力ソースへの自動切替を発動する連続誤入力の回数を設定します（初期値: 5、範囲: 3〜8）。";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.shortTitle" = "連続誤入力切替の閾値:";
 "i18n:UserDef.kBasicKeyboardLayout.description" = "macOS 基礎キーボード配置をご指定ください。注音モードと弁音モードは、現在はいつでも相互に切り替えられます。弁音モードでは、この配置が実際のキー出力を決定します（QWERTY 以外の英数キーボードも適用可能）。注音モードでは、キーは常に標準配列として扱われ、キーボードビューアの表示もそれに応じて変わります。";
 "i18n:UserDef.kBasicKeyboardLayout.shortTitle" = "基礎キーボード:";
 "i18n:UserDef.kBeepSoundPreference.option.0" = "鳴らず";
diff --git a/Sources/vChewingIME_macOS/Resources/zh-Hans.lproj/Localizable.strings b/Sources/vChewingIME_macOS/Resources/zh-Hans.lproj/Localizable.strings
index 7ef81633b..1f16b9b49 100644
--- a/Sources/vChewingIME_macOS/Resources/zh-Hans.lproj/Localizable.strings
+++ b/Sources/vChewingIME_macOS/Resources/zh-Hans.lproj/Localizable.strings
@@ -345,6 +345,10 @@
 "i18n:UserDef.kAutoCompositeWithLongestPossibleCassetteKey.shortTitle" = "在已经敲出最长可能码的时候自动组字";
 "i18n:UserDef.kAutoCorrectReadingCombination.description" = "该功能在中英混合输入回退时不起作用，以确保相容性。";
 "i18n:UserDef.kAutoCorrectReadingCombination.shortTitle" = "敲字时自动纠正读音组合";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.description" = "在「唯音-繁」中文模式下，若连续输入破坏注音结构的错误键达设定门槛，将清空组字区并输出对应英数文字，随后自动切换至 ABC 输入法。";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.shortTitle" = "连续键入错误达门槛时自动切换至 ABC 输入法";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.description" = "设定连续键入多少个错误键时触发自动切换至 ABC 输入法（预设 5 键，可选 3～8 键）。";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.shortTitle" = "连续误键触发切换门槛:";
 "i18n:UserDef.kBasicKeyboardLayout.description" = "请选择 macOS 基础键盘布局。注音打字与拼音打字现为可随时互相切换的打字模式：拼音打字时，此布局决定实际按键输出（非 QWERTY 英数布局亦适用）；注音打字时，按键一律依标准键位翻译，荧幕键盘亦随之显示。";
 "i18n:UserDef.kBasicKeyboardLayout.shortTitle" = "基础键盘布局:";
 "i18n:UserDef.kBeepSoundPreference.option.0" = "静音";
diff --git a/Sources/vChewingIME_macOS/Resources/zh-Hant.lproj/Localizable.strings b/Sources/vChewingIME_macOS/Resources/zh-Hant.lproj/Localizable.strings
index 5a159fdd8..3bb1d2f6f 100644
--- a/Sources/vChewingIME_macOS/Resources/zh-Hant.lproj/Localizable.strings
+++ b/Sources/vChewingIME_macOS/Resources/zh-Hant.lproj/Localizable.strings
@@ -345,6 +345,10 @@
 "i18n:UserDef.kAutoCompositeWithLongestPossibleCassetteKey.shortTitle" = "在已經敲出最長可能碼的時候自動組字";
 "i18n:UserDef.kAutoCorrectReadingCombination.description" = "該功能在中英混合輸入回退時不起作用，以確保相容性。";
 "i18n:UserDef.kAutoCorrectReadingCombination.shortTitle" = "敲字時自動糾正讀音組合";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.description" = "在「唯音-繁」中文模式下，若連續輸入破壞注音結構的錯誤鍵達設定門檻，將清空組字區並輸出對應英數文字，隨後自動切換至 ABC 輸入法。";
+"i18n:UserDef.kAutoSwitchToAlphanumericalOnConsecutiveErrors.shortTitle" = "連續鍵入錯誤達門檻時自動切換至 ABC 輸入法";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.description" = "設定連續鍵入多少個錯誤鍵時觸發自動切換至 ABC 輸入法（預設 5 鍵，可選 3～8 鍵）。";
+"i18n:UserDef.kConsecutiveTypingErrorsThreshold.shortTitle" = "連續誤鍵觸發切換門檻:";
 "i18n:UserDef.kBasicKeyboardLayout.description" = "請選擇 macOS 基礎鍵盤佈局。注音打字與拼音打字現為可隨時互相切換的打字模式：拼音打字時，此佈局決定實際按鍵輸出（非 QWERTY 英數佈局亦適用）；注音打字時，按鍵一律依標準鍵位翻譯，螢幕鍵盤亦隨之顯示。";
 "i18n:UserDef.kBasicKeyboardLayout.shortTitle" = "基礎鍵盤佈局:";
 "i18n:UserDef.kBeepSoundPreference.option.0" = "靜音";