Yes, you can train your vocabulary and improve your foreign language skills by listening to people talking it.
I am not a comedian, so I do not know how exactly you can make yourself funnier, but I have a very strong suspicion
that you do not become funnier yourself, by just listening to canned laughter, and that the fact that fake laughter is added to comedy shows is just to make the viewers like the show more. Listening to laughter causes most people to laugh too, even if they do not understand the cause for the laughter. For example https://youtu.be/wgzdb0txR_c?t=281 . It works with other emotions also - if someone watches or listens to an angry person, they will become somewhat angry too.
I am not a comedian, so I do not know how exactly you can make yourself funnier, but I have a very strong suspicion that you do not become funnier yourself, by just listening to canned laughter, and that the fact that fake laughter is added to comedy shows is just to make the viewers like the show more. Listening to laughter causes most people to laugh too, even if they do not understand the cause for the laughter. For example https://youtu.be/wgzdb0txR_c?t=281 . It works with other emotions also - if someone watches or listens to an angry person, they will become somewhat angry too.