[jcj]

to robin Mask

you miss the point. I am talking about starting young. I am not against native teachers teaching in schools but school age is too late for difficult phonemes. School aged kids will not get them from native or non-native conversation in any case. See Dr. janet Werker

they will get them young, and that is when the non-native teachers come in. many of the teachers teaching very young kids, in small happy groups, are non-native and they, at this age, are key.

these kids can pick up the sounds from audio devices as long as the sounds are contrasted, emphasized and given in numerous voices. (one native won't do it anyway) See Dr. patricia Kuhl.

Non-native teachers need not fret their pronunciation. Kids can get the difficult phonemes from audio visual devices. Heck, it even works with students who are supposed to be beyond the critical period for learning such things:
Zhang, Y., & Wang, Y. (2007). Neural plasticity in speech acquisition and learning.
Bilingualism: Language and Cognition, 10 (2), 147-160.