William of Tyre was a historian of the Crusades. His work can be read here:
http://www.thelatinlibrary.com/williamtyre.html
According to Wikipedia, his Latin is reputed to be particularly good (i.e. particularly close to classical Latin) compared to the standards of his time, and, having read him, I think it's probably true. Now, he does use some medieval Latin constructions and vocabulary. I found one or two downright monstrosities in his work, but overall, his Latin is good.
As for Latin being spoken in those times or not, I think it must have been spoken as a lingua franca among the clergy and educated people (who often were clergy...) but it wasn't spoken as a native language.
I'll move the thread as requested.