Sorry for coming late.. Now I got your point,, Actually there are some programming languages handle this better than PHP, like Lisp, Java, and languages related to the NLP (Natural Language Proccessing),, if you want to do it just in PHP, you will need to design a proper database for this,, it's gonna be easier if it's only a dictionary but to translate a whole clauses that would be more difficult.. am starting on something like that, so I'll tell you as soon as I handle it..
dede