I do art and science fluenty, but I still have trouble with English as I am a native Long Islander. Have take 2nd year Russian five times and still can't say much more than ordering a beer! However, I do have contacts who can read Old Persian and some dead Central Asian languages. Speaking of which, they recently found the first Sogdian sword in Central Asia. How do they know? It has a Sogdian inscription!
I would also like to make the point that being able to read/speak a current language is not the same as being able to read old or specialized texts/inscriptions. So care must be taken.
Oh, and Hubby speaks Cockney rhyming slang.