What to study first -casual English or formal English?

''When I studied German the teacher didn't come out and say "we only teach formal German here...."

This is so true, my teacher even said: don't bother with Präteritum (exept with modals and haben/sein), it's no longer used in speech.

<<I'd like to suggest "slang" for "slangs" in your posts. Also, I would try "pieces of advice" instead of the way you put it. This will make you sound more natural in English. >>

Thanks, LL. I appreciate your taking the trouble to point out my mistakes.





<<And for the billionth time, it's "slang"! NOT SLANGS! >>

So there is no such word as "SLANGS"? So "slang" can be both singular or plural? Or is the plural for "slang" is "slang words" or "slang terms"????