It seems impossible for people to debate issues of teaching and learning without piling on the abuse in the process. Maybe I'm too much of a purist in expecting people, who claim to know about teaching and learning, to focus on those topics only.

Speaking the language of the country, at whatever level of competence, does not make one an expert on education.

I'm wondering if you could "... explain a point of grammar to students who don't know any English?" How would you do it? But more importantly, why would you want to, with students at this level of competence? This is a genuine question.

You would need a very detailed knowledge of both English and Mandarin grammar to offer a cohesive explanation. Just look at passive markers in Mandarin – and there are three of them. Could you explain to a student who spoke the sentence below, why it sounds odd in English?

“My bike was stolen by him". [Punctuation here is BrE)

I do support the Communicative Approach in foreign language teaching. Students exposed to this method are given classroom activities designed to encourage them to consider and negotiate meaning in everyday conversations. This means we are teaching them, first and foremost, to be communicators. The alternative is what we see far too often in the Chinese classroom: learners who have been drilled in vocabulary and grammar, but are apprehensive about opening their mouth and using the language. And this is before we open another “debate” about ‘correct usage’ and ‘fluency’!

There is a difference between language learning and language acquisition* In the world of theoretical research, linguists, psychologists and teachers are still struggling with the concept of “comprehensible input”. We still don’t know if comprehensible input, however we define it, advances the learner’s acquisition of the target language (TL). What we do know from research is that in practice, teaching early to intermediate students in the TL uses non-verbal cues. These cues can include demonstrations, gestures, intonation cues, pictures and objects so it seems a little unfair in some of your other posts to criticise people for doing it this way. I know why you do it. It's just another broadside to stress your dislike (maybe a stronger word needed here) of training centres and the people who work there.

*See Krashen and others