What's the reasoning behind our policy against questions on a single language, and is it good?

Question

As we all know we have a policy that we discourage questions that are on a single language.

I understand that this would filter out things like English usage questions that laypeople thing often mistakenly think are in the realm of linguistics.

This makes sense because a) such questions are not linguistic and b) there is English Language & Usage specifically to deal with them, and now counterparts for Chinese, French, German, Japanese, and Spanish.

But is this the only reason? It seems that apart from this we are blocking potentially interesting linguistic question for an arbitrary reason.

If there is a sound reason I think we need a page we can use to direct people to explaining why.

If not shouldn't we rethink our rules and scope.

• Usage questions definitely don't belong here.
• Non-linguistic questions about a single language that has its own L&U site definitely don't belong here.
• But what about linguistic questions about a single language?

Answer 1

Edit: the FAQ has been reworded. (On topic questions, point number 6)

---

Well, maybe the FAQ needs some re-wording but it's more or less like this. Basically we discouraged, or intended to, very easy questions like etymology ones. But I have an idea:

We can accept single words questions as long as:

1. There is an evident research effort in the question;
2. The question is related to Linguistics and it's not simply a language question.