Including a GPL dependency doesn't mean the whole code has to be on GPL.
You can just release it as MIT with a Phonemizer as a GPL dependency. If a business makes a product out of your code, it will have to track the individual licenses of any dependency anyway.
In fact, there are projects that have a mix of GPL and MIT code in a single repo. If someone ever decides to rewrite GPL parts, they'll be left with a pure MIT. While GPL parts are left, the whole binary is considered a GPL.
Thus no reason to change phonemizers if all you need to do is to change a license.
Including a GPL dependency doesn't mean the whole code has to be on GPL.
You can just release it as MIT with a Phonemizer as a GPL dependency. If a business makes a product out of your code, it will have to track the individual licenses of any dependency anyway.
In fact, there are projects that have a mix of GPL and MIT code in a single repo. If someone ever decides to rewrite GPL parts, they'll be left with a pure MIT. While GPL parts are left, the whole binary is considered a GPL.
Thus no reason to change phonemizers if all you need to do is to change a license.