I think the pronounciation option is part of the TTS voice, and Hal's option just lets you access it. With the voice I use, I can't change the pronounciation at all - absolutely nothing happens when I click the "Pronounciation" button!
This is immesurably frustrating when I give my bot a name like "KAOS," which my TTS voice insists on pronouncing "cows."
Perhaps try some other TTS voices, maybe you'll have more luck with another one.