Na und?

Snapshot from a discussion about English usage:

This is probably why Japanese tend to accept what the Kenkyusha Unabridged Dictionary of English says is good usage rather than believing what an educated native anglophone says. The dictionary always has the same answers no matter which edition or which copy they consult, but we native speakers of English almost always provide different answers for all the obvious reasons. You should hear me exclaim "Oy!" when my son tells me what his 4th-grade Taiwanese English teacher tells him about my native language. Naturally, though, he believes her version.

Franke: EFL teacher and medical editor
It's all in the way you say it, innit? [ isn't it]

Yes, and that's why trained translators will always be faster than native speakers. Unencumbered by the 24/7 experience of the language, its subtleties and ambiguities, they find the one and only right word for the translation quickly. At best they are correct but sound generic. At worst they get a phrase or an idiom completely wrong. Na und?