diff --git a/Rules/Languages/de/ClearSpeak_Rules.yaml b/Rules/Languages/de/ClearSpeak_Rules.yaml
index 4c8f1d277..8d23c3502 100644
--- a/Rules/Languages/de/ClearSpeak_Rules.yaml
+++ b/Rules/Languages/de/ClearSpeak_Rules.yaml
@@ -532,37 +532,46 @@
   - x: "*[2]"
   - pause: short
   - test:
-      if: "not($is_intervals_start_infinity)"
+      if: "not($is_intervals_start_infinity) and starts-with(name(.), 'open')"
+      then:
+      - T: "nicht einschließlich"
+      - x: "*[1]"
+  - test:
+      if: "not($is_intervals_start_infinity) and not(starts-with(name(.), 'open'))"
       then:
-      - test:
-          if: "starts-with(name(.), 'open')"
-          then: [T: "no"]
       - T: "einschließlich"
       - x: "*[1]"
-    # logic to deal with [not] arg #1
   - test:
-      if: "not($is_intervals_start_infinity or $is_intervals_end_infinity)"
-      then_test:
-      - if: "name(.)='open-interval'"
-        then: [T: "ohne"]
-      - else_if: "name(.)='closed-interval'"
-        then: [T: "mit"]
-        else: [T: "ohne"]
-    # some ugly logic dealing with connectives: or, but, but, and (cleaner to be part of next clause?)
-  - test:
-      if: not($is_intervals_end_infinity)
+      if: "not($is_intervals_start_infinity or $is_intervals_end_infinity) and name(.)='open-interval'"
       then:
-      - test:
-          # there is some asymmetry to the test because of the and/or/but logic above
-          if: not( name(.)='open-interval' or name(.)='closed-interval' ) or $is_intervals_start_infinity
-          then:
-          - test:
-              if: "name(.) = 'open-interval' or name(.) = 'closed-open-interval'"
-              then: [T: "ohne"]
-          - T: "einschließlich"
+      - T: "und nicht einschließlich"
+      - x: "*[2]"
+  - test:
+      if: "not($is_intervals_start_infinity or $is_intervals_end_infinity) and name(.)='open-closed-interval'"
+      then:
+      - T: "aber einschließlich"
+      - x: "*[2]"
+  - test:
+      if: "not($is_intervals_start_infinity or $is_intervals_end_infinity) and name(.)='closed-open-interval'"
+      then:
+      - T: "aber nicht einschließlich"
+      - x: "*[2]"
+  - test:
+      if: "not($is_intervals_start_infinity or $is_intervals_end_infinity) and name(.)='closed-interval'"
+      then:
+      - T: "und"
+      - x: "*[2]"
+  - test:
+      if: "$is_intervals_start_infinity and not($is_intervals_end_infinity) and (name(.)='open-interval' or name(.)='closed-open-interval')"
+      then:
+      - T: "nicht einschließlich"
+      - x: "*[2]"
+  - test:
+      if: "$is_intervals_start_infinity and not($is_intervals_end_infinity) and (name(.)='open-closed-interval' or name(.)='closed-interval')"
+      then:
+      - T: "einschließlich"
       - x: "*[2]"
 
-    # onto the [not] [including]... part
 - name: binomial-frac-vector
   tag: matrix
   match:
diff --git a/tests/Languages/de.rs b/tests/Languages/de.rs
index 4d2be48ab..b2c36e61e 100644
--- a/tests/Languages/de.rs
+++ b/tests/Languages/de.rs
@@ -2,6 +2,7 @@
 
 mod ClearSpeak {
     mod functions;
+    mod intervals;
     mod large_ops;
     mod menclose;
     mod mfrac;
diff --git a/tests/Languages/de/ClearSpeak/intervals.rs b/tests/Languages/de/ClearSpeak/intervals.rs
new file mode 100644
index 000000000..3bf359a55
--- /dev/null
+++ b/tests/Languages/de/ClearSpeak/intervals.rs
@@ -0,0 +1,149 @@
+//! Regression tests for German ClearSpeak interval endpoint wording.
+//! Each endpoint combination should use one German connector and no untranslated words.
+
+use crate::common::*;
+use anyhow::Result;
+
+#[test]
+fn interval_open_open() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis d, nicht einschließlich c und nicht einschließlich d",
+    )
+}
+
+#[test]
+fn interval_open_closed() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>]</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis d, nicht einschließlich c aber einschließlich d",
+    )
+}
+
+#[test]
+fn interval_closed_open() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>[</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis d, einschließlich c aber nicht einschließlich d",
+    )
+}
+
+#[test]
+fn interval_closed_closed() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>[</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>]</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis d, einschließlich c und d",
+    )
+}
+
+#[test]
+fn interval_negative_infinity_to_open_endpoint() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mo>-</mo><mi>∞</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall negative unendlich bis d, nicht einschließlich d",
+    )
+}
+
+#[test]
+fn interval_negative_infinity_to_closed_endpoint() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mo>-</mo><mi>∞</mi><mo>,</mo><mi>d</mi></mrow>
+        <mo>]</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall negative unendlich bis d, einschließlich d",
+    )
+}
+
+#[test]
+fn interval_open_endpoint_to_infinity() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>∞</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis unendlich, nicht einschließlich c",
+    )
+}
+
+#[test]
+fn interval_closed_endpoint_to_infinity() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>[</mo>
+            <mrow><mi>c</mi><mo>,</mo><mi>∞</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall c bis unendlich, einschließlich c",
+    )
+}
+
+#[test]
+fn interval_between_infinities_has_no_endpoint_qualifier() -> Result<()> {
+    let expr = "<math>
+        <mrow><mo>(</mo>
+            <mrow><mo>-</mo><mi>∞</mi><mo>,</mo><mi>∞</mi></mrow>
+        <mo>)</mo></mrow>
+    </math>";
+    test_ClearSpeak(
+        "de",
+        "ClearSpeak_Paren",
+        "Interval",
+        expr,
+        "das Intervall negative unendlich bis unendlich",
+    )
+}