TEACHERS, this question is for you: How important are SLANG & IDIOMS in language learning? Do you teach them in your classes?

STUDENTS, this one is for you: How do you like learning SLANG & IDIOMS in your classes?

I found a very interesting article about it. It's really worth reading:

LINK: http://matadornetwork.com/abroad/how-important-are-slang-and-idioms-in-language-learning/