I started to take an interest in Libras (a.k.a. Brazilian Sign Language) after watching Libras interpreters in my Accounting video classes. I was just fascinated by how they could convey such complex words and concepts through mere hand gestures and facial expressions!
Back when I studied Letters (i.e. Language Studies), my university offered a course in Libras. It was (and still is) compulsory for all students in any area who wanted to be teachers in Brazilian schools. Since I didn't want to be a teacher, I never felt the need to study it. Now I kinda regret not taking that course, because not only is it really interesting, I could have gotten some extra credits from it, haha.
Anyway, I've decided to do some reading about it and watch some online classes on YouTube. Apparently, Libras was largely based on the French sign language, but it's also borrowed some signs from ASL. I also read that sometimes different sign languages can be more or less mutually intelligible, much more so than spoken languages. I wonder, how much of Libras would an American who knows ASL, for example, be able to understand?
Here's a very nice video (with Portuguese subtitles) with basic greetings and dialogues in Libras:
Click to view
ETA: Another very good video with oral explanations in Portuguese:
Click to view