It would be nice to see a section on here for "slang"
I can't count how many times I have heard people in brazil use slang to me. I'm not sure how often it happens in other languages because I've only been to brazil, but every time I go out and hang out with friends they begin to use slang. I'm confident most of the time when talking in Portuguese but when someone begins to use slang, I think to myself "Diabéisso?!" ( hopefully I used it right). But anyways while studying a language, put some time in to learning some slang as well. Not only will it help with having a good conversation, It will also impress many natives of that language and maybe even give them a good laugh with some funny phrases. Anyways, I know I didn't discuss "De cabo a rabo", just thought I would throw it out as some advice. Here is a link to a Brazilian slang website (some of the phrases have profanity in it so be aware), hope this is useful! http://speaklikeabrazilian.com/en/top?page=1
I know as a native English-speaker that this would be difficult to do for English. Slang constantly changes and words and phrases go in and out of fashion, sometimes very quickly. Example: If you watched the TV show "Seinfeld" in the 1990s you undoubtedly heard his catchphrase "yada, yada, yada." It caught on with the general public for a few years but then went out of fashion almost as quickly as it came in.
I completely support the idea of a slang lesson (bonus or otherwise), but this is a real problem. It would need to be updated so regularly.
Also, slang is incredibly regional. In Ireland alone, a small country, there is considerable difference in the slang used in different parts of the country. From my experience in South America (excluding Brazil), the slag in each country changes quite a bit.
But yes, it would be nice if there were slang skills.
Beginners may want to learn a couple but it doesn't have to be a lot, they could make slang a bonus skill and not a necessary requirement. One word that they use in Brazil is "Saudade" and this can be translated simple but there is no translation in English that is equivalent (they might have in another language but I'm not sure). If beginners can get a handful of slang words at some, it could help a lot in some future time so at some point they will have to learn.
I completely agree. I've competed Duolingo for German and French and have since started speaking with natives in those languages. The amount of words that could be considered slang that I've had to learn is astounding! Just a simple thing, such as saying "Ouais" instead of "Oui" for example. When you're familiar with someone and it's informal, I do say "yeah" more than I say "yes"; it's easier, and doesn't sound too robotic.
I agree with other comments too that maybe it's not best for beginners to learn, and yes slang does change, but the fact is, people do use it in normal day to day situations. The German fellow I'm speaking to constantly tells me to speak to him as if he were a native, so that he can learn the language naturally, and so that I'm not censuring my slang. It helps him to learn better. Therefore, I think it's situation specific. Agree what's acceptable with a language partner, and go from there! Personally, I love learning the little words like "Jup" and "Juhu!".