I think this concept will beat-out Google and others... Have a checkbox to display a third text frame that will show a phonetic version for the target language. The goal being to help the user (learn how to) say the phrase. It would be best if it showed along with the normal text so the user can correlate the two. There are also potentially two kinds of "phonetic". The primary (initial effort) would be the standards used in dictionaries. The other "seriously cool" version is to use syllables from words in the user's own language. This second approach is "out of the box" thinking that would also beat-out Google, etc.
I agree. It would be quite useful to know how to pronounce accurately a word according to International Phonetic Alphabet: