Slang: this is a non-count noun. Please don’t use it a a count noun! “I would like to learn some slang.” is correct, but “I would like to learn some slangs.” is not.
“Slang” can also be an adjective: “I would like to learn some slang words.”
Some people think that “slang” always means “rude, impolite, dirty words.” This isn’t totally correct. While many swear words are slang, not all slang is rude. You might use slang at work. As examples, restaurant workers call a table for four people a “four-top,” and IT workers often call a desktop computer a “box.”
Jason: Hey Ritchie, is that four-top in your section ready for drinks yet?
Ritchie: Yeah, they want three light beers and a glass of red wine.
Liz: I can’t believe it. I just set up those six Windows boxes for the daycare yesterday, and they’re already broken! The children here have no respect!