I live in Uruguay (South America), many developers don't speak English, and most that do don't speak it well (they usually do read and write decently).
You'd probably be hard pressed to understand what they're talking about :) - for example JSON is definitely JASON, and you'll be looked at funny if you don't pronounce it that way :) , and Ajax is pronounced like the Dutch football team.
If I don't hear it on a video or a talk, I'm probably pronouncing it wrong (and not knowing I am). I hope to get corrected if I do.
I guess its important to make allowances - especially for non-native English speakers.
I worked on a portlet system a few years back (oh the horror!) with a Chinese dude. Super developer. It wasn't until the last day that I figured out what he meant when he said 'poorer led'. Should have figured it out sooner looking back :D
Someone like me probably set them down the wrong path!