Chat in English (英語で雑談) Part 147
A native English speaker is not necessarily good at English teaching.
He must know how to teach English, of course.
For example, he must know English grammar.
A native English speaker doesn't necessarily know English grammar as taught in Japanese schools.
Moreover he should know Japanese people's way of thinking.
For example, he should know what is difficult for them to learn English.
Also he must speak Japanese fluently.
Usually it's hard to find a native English speaker who satisfies those conditions.
A more practical strategy is this:
Learn English from a Japanese teacher and use a native English speaker as an informant
who shows correct pronunciation, usage etc.
This strategy is usually taken in English teaching TV programs of NHK.