If you are after a ready-made solution, sorry can't help, but I have a URL for an excellent 'C' English-to-phoneme translator.
A while back I was looking for something that was good enough to recognize KALKYOULAYTOR as CALCULATOR, I never found it but this is the closest I came across. It is based on the NRL report "Automatic translation of English text to phonetics by means of letter-to-sound rules" and has very good in-code documentation of the technique used.
You could (with out too much trouble) get the rules and pseudo code from english.c and implement this in progress. It uses simple string manipulation that could be implemented quite well in progress with SUBSTRING,MATCHES and BEGINS statements.
Another option is to use the C code to create an ActiveX or DLL routine and call this from progress (much faster, but you will need C skills and a Compiler, you will also have to the ship/register your DLL/OCX with your application).
English to Phoneme Translation