Well, it's true that most my my colleagues can read English well enough to get the gist of docs and Stack Overflow, but when it comes to speaking, they don't know how to pronounce a lot of the words, to the point of being very difficult for the listener to understand, and struggle to put together a coherent sentence (particularly in the short timeframe needed to have a smooth conversation). They also find speaking English to be highly stressful and generally avoid it as much as they can.