This paragraph in particular:
It is brutally hard for most people (after the age of puberty, and perhaps especially for males) to learn to attend to sound distinctions that don't exist in the learner's native language. That is especially hard when the sound distinction signifies a grammatical distinction that also doesn't exist in the learner's native language. For example, the distinction between "I speak" and "he speaks" in English involves a consonant cluster at the end of a syllable, and no such consonant clusters exist in the Mandarin sound system at all. Worse than that, no such grammatical distinction as "first person singular" and "third person singular" for inflecting verbs exists in Mandarin, so it is remarkably difficult for Mandarin-speaking learners of English to learn to distinguish "speaks" from "speak" and to say "he speaks Chinese" rather than "he speak Chinese" (not a grammatical phrase in spoken English).
One thing I've noticed is that there seem to be relatively few super-successful Chinese immigrant founders in the USA. Fewer than Indians for example, even though both are large immigrant communities. My wife is Chinese and her theory is that Chinese aren't really good at teamwork. I think it has more to do with their difficulties in catching the subtleties of the language as described above.
It is not quite a problem of them not communicating their message well, I think. Most of the time they do, although it may not aesthetically be very pleasing. It is more an issue of them missing alot when you speak to them, unless you conciously try to adapt to your audience.