I noticed that on this ELU help page, where new users are informed about what kinds of questions they should (and shouldn't) ask, there is already a link to Writers.SE. I wonder if it's not time to add another link to ELL.
The site for English Language Learners was stood up in large part so that non-native speakers could have a place where their questions, which would be regarded by some to be "too basic" for ELU, could ask their questions. The site was stood up in January of this year. There have now been over 2,500 questions asked on ELL, and the site is averaging over 1,000 visitors per day. I think ELL is now stable enough that the ELU help page could give it a mention, saying something like:
in the same section where it already says:
But please, don’t ask any questions about the following topics. They are out of scope for this site.
- Proofreading ("are there any mistakes?"), unless the source of concern is clearly specified
- Writing advice or critique requests (see Writers.SE instead—note critique requests must meet their criteria)
I still see quite a few new users asking questions that get downvoted and/or closed on ELU, with comments that essentially say, "You would have been better off asking this on ELL." (See, for example, 121300, 118493, 122209, 121881, and 113573.) Yet it's hard to imagine how a new user would have known about ELL's existence if they happened to stumble across ELU first.
It seems like both sites would benefit from a pointer on the main help page, as would many new users. (It need not be worded the same was as in my example; someone else may have a better way to word it.)
As an option, there might also be a pointer to this meta post.
Related: FumbleFingers' Feb 5 2013 answer to a similar question. (This issue has been raised before, but was last mentioned when ELL was still in its infancy, and many thought that posting a link then would be premature.)