Ah. After my own heart. But I doubt you'll have much luck. Still, if you're willing to go through with it, develop a proof-of-concept. Even if it fails, it'll still be a good experiment.
Concept? List all the words and their meanings + list all the idioms with their meanings. Next step while translating to THE language writer will be asked which time it is, what he/she wanted to say with these words, what are the meanings etc. This should translate from imperfect human language to a perfect computer language with just a bit of help from human. Then translating from perfect language to any human language shouldn't be hard for program.
BTW, while you're at it, work out how you'd encode "After my own heart" to make sense in other languages. :)
Make a list of al English idioms and theirs equivalents in other languages. Forst the program will check if in the sentence to translate are any idioms from the list. If not then it will translate just the words.
I started writing the translation application, but I am not a good programmer, so I don't know when will I be able to show you smth that works...
Regards, Talthen