Commonly used in the English language as an informal way of saying hello, I have - as a semi-obsessive fan of the Rocky series - for years adopted 'yo' as a substitute for 'hi' or 'hello', really without any issues.
That, of course, was before venturing over here to Europe.
While living in Budapest last year, I discovered that 'jó' which is pronounced 'yo', means 'good'. So naturally, I'd get some weird looks the first few weeks I was there when I'd greet someone with a 'Yo, what's goin' on?'. Eventually, as I picked up on the language, I started to get less odd looks from folks when I was greeting them.
Then I got to Prague a few months ago, and quickly discovered that 'jo', which is also pronounced 'yo' in the Czech language, means 'yes'. (To make things even more difficult for this hard-headed American, 'Ano' also means 'yes', but it can be pronounced 'ahn-yo' or just 'no'. Uh, you see what I'm working with here?)
Okay, so now I'm thinking that I'm already completely messed up trying to learn bits of this new language, and things only got worse when I met a guy from Barcelona and tried to impress him and dig up the little Spanish I recalled from four years of studying the language in high school. As you Spanish-speaking folks know, 'yo' in that language means "I'. As they say on ESPN's NFL Primetime, 'C'mon maaaannn!'
Whoever decided hundreds of years ago that crossover words in different languages was a good idea, definitely had a sense of humor.
So, I'm still struggling with grasping the different uses of 'yo' after nearly four months here in the Czech Republic and almost a year in Europe all together. When I'm coaching, there have been several times where someone will make a good play and I'll blurt out 'Yo!', and then stop and try and figure out what I just said to them.
So when I get back to the states in the fall, if I see you for the first time and say, 'Yo, what's up man?' and then pause for a time afterwards, don't be offended. It's just the language gears churning, and I'll be with you in a minute.