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.