As BJ and Sirius have said previously a vocooder or text2speech software may get you the results you want. If you use the Text2speak software get it to say individual words rather than sentances then assemble them together to get what you want. This help a little get rid of the crap pronounciation some of these programs have.
Alternativly find yourselve an old Texas Instrumnets Speak and Spell from a charity shop,ebay or booty. They are worth a fair bit to some producers believe it or not lol. There is a software version but i havent personally used it,could be fun.
Speak n Spell 