Jeebus, I'm now reminded of some of the weird ass slang I heard when i went back to my home country after like 5 years. My home country being Malawi (so I guess I'm adding some spice to this thread as most entries have been of western origin).
Oti (oh-tee): pretty much the equivalent of 'bloke', 'dude', usually used when referring to someone of one's acquaintance who others might not know, e.g: "yo, it was this one oti from souths" or "nah, its just some oti i know."
assé (ah-seh): probably not written with an accent on the e, but it sounds that way. I can only deduce that is pretty much the Mexican 'Essé' but now being pronounced by a different group. BUT while 'essé' is usually used to refer to a person, 'assé' is kinda tossed around as all purpose filler word at times e.g: "Yo assé, let borrow some shit from you." or "Dude assé, i don't even know what he was thinking." or sometimes as a reactionary word: *gets told some bad news* "Aaah, assé, area you serious?" or "Assé... thats not fresh."
Tune/Tune-out (usually pronounce 'Choon'): basically to talk someone out or to lecture someone, like when authority figures are expressing disapproval to youth antics, said youth would tell his friends: "yo, they were tuning me out for that shit." or even when people of similar hierarchy are doing to it: "This one oti kept tuning me out about it." or "see we go tune him out then." (note: 'see we go' is a pretty common African way of saying 'okay, lets go', you will here it being being said in most East African/Southern African countries)
there are others, but my mind can't be assed to remember them or what they meant, though a recent one I heard that sounded fishy to me was 'franchise', which i didn't get the full explanation on but I believe its the name given to group of people that import technological goods... but to me it sounds like slang for a gang or something.
Actually though, during my highschool days in Kenya, me and my male classmates turned the words 'Bump' and 'Bash' into all purpose verb words for 'do the thing', e.g: "lets play some COD" would become 'Yo, we bump/bash COD'. sometimes used in past tenses like: "hey are people attending the disco?" to "are guys bashing disco?". in its most abstract of uses 'bash' could be used as such: "hey could you copy CSI season 5 on to my hard drive?" to *throws hard drive at friend* "yo bash CSI season 5."