I had a similar issue when subbing an english doco into greek and turkish too.
We searched around for a possible automated solution for the translations, even looked at babel fish, but in the end, the best way we found was to hire a human translator, as a word for word translation engine might misread something you type. EG: Read and Read; you might mean present tense, but the app might take it as past tense, and translate incorrectly.
Another reason for using a person for translation will mean that they can craft the words a little more to fit the prose/grammar of the final language as often times a word for word translation just doesn’t evoke the same message.
So for our Turkish & Greek translations, they then re-worded the script, typed it up in Word, then it was just a matter of copy and pasting the correct words (and accents etc) into FCP. (we needed embedded subs on video otherwise we would have done it in DVDSP as an independent sub track on the DVD)
The only issue I can see for this method, is whether FCP or DVDSP supports Cantonese/Mandarin/Korean character sets. Can anyone else answer that?
Anyway, paying for a translator for every project may be more expensive than using a less accurate one-time cost application, but in my experience, bad subs, like bad audio can really bring down good pics and the viewers whole experience.
Simon