What is the difference between the "English Language & Usage" and "English Language Learners"?
Could anyone clarify the differences?
Which questions should I ask here, and which ones should I ask there?
Although there are a number of differences between the two sites, the key difference is right there in the name:
English Language Learners (ELL) is about helping people learn English
English Language and Usage (ELU) is really about the study of English Language and Usage from a largely academic perspective.
If your question is really about how to speak, read or write everyday English, it probably belongs on ELL. If your question is about historically why things happen they way they do in English, or about how to speak, read or write specific uncommon or obsolete dialects of English, it probably belongs on ELU.
For some time now, I’ve thought this was less about the particular question being asked than it is about the kind of answer being sought.
If you are learning English, and you’re struggling with some particular issue, and you’d like some native speakers to help guide you, then there’s a good chance that ELL is the right place to ask. That’s what the ELL community is designed for.
However, if you’re wanting a more technical answer from a linguist, you’d be better off asking on ELU.
I like to say that ELU is the place to go when you want a “John Lawler” answer. (Professor Lawler is an ELU regular who understands the semantics of English quite well, and explains them quite thoroughly.) Here are a couple excerpts from John Lawler's answers:
The OP also notes that these cookies is the Direct Object of the infinitive to make and normally what one expects to be moved or missing from an infinitive is its Subject, not its DO. And indeed the subject of each infinitive is missing, but that's normal for indefinites. The real question is how the infinitive make wound up shorn of both its Su and its DO, and how the DO of make wound up as the Su of be fun. And the answer is a minor governed cyclic rule called Tough-Movement.
This that is not a demonstrative pronoun, and does not refer to a neuter noun; it's a complementizer that introduces a tensed subordinate clause, and it's used in English also to mark subject and object complement clauses.
If that’s the kind of answer you’re looking for – one that might be a challenge for the layperson to come up with – then ELU would be the place to ask.
But if that kind of answer would be “overkill” for what you are trying to figure out, then ELL might be the better place to ask – particularly if the main reason for your question is that you’re not a native speaker of English.