"Q: When native speakers of English teach English, they naturally do it based on their own cultures. Why is this a problem?
A: When you teach a language, you teach the principles, the mind-set, ideology and philosophy, everything that goes with the culture of the people of that language. I think this is not fair.
When Americans teach English in Japan, for example, they will expect you not just to speak the language, but they will expect to put American minds into Japanese bodies. Why can't they speak English and still be Japanese? Why do you have to speak English like an American?"
Ginko Kobayashi / Special to The Daily Yomiuri
I think he is missing the point in an excess of nationalism.
When you teach a language you need to teach the learner to think like a native speaker of the language. This is not the same as saying you need to adopt their philosophy of life. Americans and British for example may have different philosophies of life, but they "think the same" when it comes to how they describe the world through language.
An illustration from Spanish. In English the subjunctive is virtually a dead duck. Spanish uses the subjunctive all the time.
Busco al hombre que habla inglés. (I am looking for the man who speaks English.)
Busco a un hombre que hable inglés. (I am looking for a man who speaks English.)
In the first case the speaker uses the indicative because he believes the man exists, in the second case he uses the subjunctive because he does not know he exists. This distinction is made by all native Spanish speakers whether they live in the High Andes or on the Costa del Sol. Every native speaker of Spanish is continuously assessing (sub-consciously at least) whether the situation is hypothetical or doubtful, relates to the future etc in a way that native English speakers do not, as their language does not require them to make the same distinctions as Spanish. If you want to speak Spanish "like a native" you need to think like a native Spanish speaker, or if you like a Spaniard or Peruvian. This does not mean that you need to become a Roman Catholic and appreciate the finer points of bulfighting.
Japanese, a language I have studied cursorily, is far more different from English than Spanish. I am sure the basics of English are as difficult for the Japanese to grasp as the basics of Japanese are for the English to grasp. In both cases teachers need to break down the linguistic preconceptions of the pupil. This may involve asking the pupil to forget, for the duration of the lesson, that he is English/Japanese.
When the pupil has advanced it is necessary to introduce to the pupil to some "real" examples of the language. This of necessity involves examples written by native speakers. I doubt there is any Japanese literature written by Englishmen or Japanese literature written by Englishmen.
When I speak Spanish I become a slightly different person - not a Spaniard, but an Englishman in Spanish clothes.