Steven Pinker uses the term “tin ear” in talking about people who barrel through the genius of the English language, destroying syntax and morphology in their wake, to the ultimate goal of being “proper”. These are the folks who will observe the “split infinitive” nonsense no matter how absurd it makes their speech.
Why is this? It is b/c some people are rule-bound. Their life revolves around following rules so they can control everything and everybody, be armored against criticism (“but it’s a rule”), and feel that they are being proper at all times. One can easily imagine how these people were raised and schooled.
For them, the idea of using L2 in the classroom without being absolutely sure of the correctness of everything uttered, by them and by their students, is anathema. This accounts for much of the discord on fl teacher listservs, the clash of these folks with less bound people.
The term “accuracy” has come to be used to refer to well-formed sentences in the TL. This means the sentence conforms to what a native speaker would say. It doesn’t mean that anything less is incomprehensible or should be rejected and it doesn’t relinquish the goal of native-like speech. The term accuracy also works better than ’correctness’ b/c it gets us away from the Doctrine of Correctness in English which dictates following rules no matter how much they fail to match with English usage, the so-called “tin ear”.