Slang language

What do you think about slang language? And how many people use slang language in your country? In my opinion, slang language is very useful, easy and many teenager use the slang but why this language have bad image for there parent or another adults? Some slang language has made simple words or short words but after teenagers using a expletive words or sexual jargon so now we have this problem. 

How to change there? I think, this problem couldn't change because slang is same to culture  if there are blocked the this words, maybe teenagers are more using this words but if their recognize to mistakes, themselves are plucked to change.