Most 4-week crash courses offered by commercial providers do not cover enough educational
background theory needed for the classroom, they do not cover English Grammar for ESL,
and they do not introduce the trainee to a wider spectrum of teaching methodologies and
generally rely on one methodological approach only. Some of these folks graduating from
such a crash course even do not know how to do textbook analysis or even write a decent
lesson plan. Many of them confuse "it's" and "its" in their written
English and are unaware of the mechanisms underlying this difference in spelling.

Agree! The minimum TESOL study requirement should be examined. 4-week, 100 hours is not enough.

However, I think there are many instances when a decent Chinese English teacher can teach English grammar better than NES. My school has intensive IELTS courses for Grade 11 students and they won't let an FT anywhere near the classroom (including an American colleague with a PhD in linguistics).

You are a non NES, so you should be fully aware of the pragmatic approach to grammar that is not often used by NES.

I have a colleague (Chinese), who has been teaching English for 26 years yet she still often asks me to help her with language points.

Yesterday, for instance, she called me to ask me if we say 'is a couple' or 'are a couple'? (As in, 'there is/are a couple of eggs in the fridge).

Her confusion? If we say 'there ARE a couple of eggs in the fridge', then why do we also use a contraction and say 'there's a couple of eggs in the fridge'?

Even after 26 years, collective nouns are still a problem for her.

English can be a real 'bitch' sometimes - especially for ESL learners, and teachers too.

As for spelling, I often feel quite relieved that Chinese students text each other in Chinese. If they used the western system (nice 2 C U M8), then we would be encountering many of the problems that teachers are facing in western countries. I saw an article on the internet a few weeks ago about how 'text speak' is literally screwing up students ability to spell correctly. If I find it, I'll post the link here.