Ah ... so maybe I'm looking at this too broadly. This thread was a call for source suggestions for an instant answer multilingual translator.

Sticking to that topic, I can say without reservation that there is NO existing project that meets the stated requirements unless it is being worked on privately and just hasn't shown up on the radar yet. The only decent third party sources are Google (which I don't think offers a useful API for this), and Bing.
posted by [UserVoice Brent] • 4 years and 3 months ago Link