Thank you all for your responses.
It's nice to have a fruitful discussion about the relation beween learning linguistics and teaching English.
drhatch, your story that many TEFL teachers are not
very aware of linguistic theories is very interesting for me.
I know a native teacher who has a TEFL certificate but frequently laughs at
his students' mistakes.
Not to mention, this kind of attitude is unprofessional and disappointing,
but, at the same time, makes me wonder whether TEFL (or TESOL)
teachers are knowledgeable about linguistics.
Though Chomsky says that the most important task for a language teahcer
is to attract his/her students' attention,
I believe that learning linguistic theories brings a lot of benefits to foreign language teaching.
If they learn applied linguistic theories such as error analysis or affective filter hypothesis, they can detect the cause of their students' mistakes or errors
and will never look down on them.
If they learn phonetics, they can correct their students' pronunciations.
This is more constructive than complaining about their students' "thick accents".
If they learn syntax, they can correct their students' grammatical errors more effectively.
