The best courses I'd recommend are Thorsten's at Parma Tyelpelassiva (
LINK).
However, if you're just looking for a few insults, I suppose you could look for a phraselist. Though some are slightly incorrect or need to be updated (like those that use -ch for "you").
As for no one speaking Elvish these days, it's just a hiatus as we digest and comprehend the massive amount of information published in the latest issue of Parma Eldalamberon, which has changed quite a lot of our previous usage. So it'll be back.