Indeed, like liz already explained (but I would just like to confirm it here): the text you see on the buttons are the default text that is fed to the speech synthesizer. You can however also enter a 'phonetical text', which you can enter in any way you like to make it sound right.
in reply to Re: slightly OT: Translators wanted for pVoice
in thread slightly OT: Translators wanted for pVoice
This is not always needed. The BrightSpeech synthesizer liz mentioned (the Flemish speaking female) has a phonetical lexicon which you can feed, so you don't need to enter a specifical phonetical text.
Jouke Visser, Perl 'Adept'
Using Perl to help the disabled: pVoice and pStory