Is it possible to become a TEFL-teacher even if English isn't your native language?

Answer 1

Yes it is. But (a) your English must be very good, and (b) you must pass the TEFL examinations.

The main disadvantages for someone whose native language is not English are:-

1. they will be unlikely to appreciate some of the the subtleties of meanings of English words, expressions and idioms
2. they will be unlikely to know 'instinctively' what the correct grammar should be for every situation
3. they may be influenced by their mother tongue so much that they may find themselves teaching some form of 'hybrid English' that is not actually standard English!
4. they may not spot the mistakes of the learners. To the native English speaker, learner errors and mistakes stand out a mile!
5. they will not have the 'authority' (in their student's eyes) of being a native English speaker.

Grammar and complex sentences

In everyday speech a native English speaker will automatically know what to say and how to say it. They will also freely switch tenses, as necessary, throughout the conversation, even within one sentence, and complex sentence structures are formed with ease, without even thinking about it.

To become proficient, a learner of English needs to become versatile and adept in these matters with their English language skills. It would seem that a teacher whose native language is not English would possibly be at a disadvantage and unable to provide the model of English 'speaking' that someone whose native language is English will be able to provide for their students.

Rhythm and stress

Spoken English has a distinctive rhythm, and the stress patterns of English words are also important. Those whose mother tongue is English will have been exposed to the rhythms of the English language from birth, and even from before birth, while they were still in the womb.

On the other hand, speakers of English whose native language is not English are very likely to have developed their own rhythms of speech based on their own mother tongue. Consequently they will find themselves teaching a stilted form of English. The words may be right, and the grammar may be correct, even the pronunciation may, with effort, be very good, but, unless the 'foreign' teacher has outstanding language skills and has spent sufficient time becoming very proficient with their 'natural-English' speaking skills, what they say and how they express themselves may not provide the best example of native English speaking for their students.

Culture

English words and styles of speech are very much a product of English culture, in all its various forms. It will be an exceptional person who, although not having English as their native language, is able to communicate the true flavor/flavour of the language.

Summary

It is possible for someone whose native language is not English to become a TEFL-teacher. In large measure this depends on (a) how proficient they are, and (b) the level of ability to which they wish to teach their students.

Furthermore, and perhaps even more importantly, to the extent that the potential TEFL-teacher fails to address, or is unable to address, their 'own native language' challenges enumerated above, to that extent their success as a TEFL-teacher may be limited.