"There is no place in the world with a high standard of English as a foreign language where a majority, or even a lot, of the teaching is done by foreign teachers.
Think of a few places you know where there's a high standard of English? It should be easy because there are a lot of them: places like Holland, Belgium, The Philippines, Switzerland, Sweden, to name a few. Not a single one of these countries has a significant number of foreign teachers. Probably every single one of those European and South American businessmen you know who speak flawless English was taught by a local teacher. The Filipino, Indian, and Malaysian students at you school were all taught by local teachers.
I know, I know, Dutch is very similar to English, and in the Philippines and India, English is the language of the professional class. Things like this make it much, much easier to learn a language. But not only is this not particularly true in some of the places where English is best spoken, but it's not even particularly important. What is important is that there are plenty of places where having been taught by a properly trained local teacher is not a significant handicap.
Let's look at the flip-side of this problem. Have foreign teachers made a big impact in the places where they are widely used? In Japan, virtually every school in the country is provided by either the JET program or other locally developed programs with a foreign teacher. The next largest foreign teacher programs are Korea and Taiwan. All of these countries are notorious for the poor standard of their English compared with, for example, Scandinavian countries. In fact, if you look at it this way, it's the countries with the worst record that have the most foreign teachers.
There are many excellent foreign teachers who have made a big difference to their students. But that's not the point. My point is that there is no place on Earth where English is spoken widely as a foreign language where most, or even a lot, of the teaching is done by foreign teachers. Being taught by competent and skilled local teachers will never be a disadvantage to a learner."
I would quibble with Scott that the standard of English in Switzerland is high (mainly because the Swiss have traditionally learned one or two of the four official languages as second and third languages in school). But other than that his point is well taken.
Source:
http://scottsommers.blogs.com/taiwanweblog/2007/06/are-native-spea.html
