I don't know if you're joking or not, so I'll answer as if this were a serious proposal.
ELL is a serious StackExchange site like any other, centered at trying to help people learn English. If people are posting "garbled questions or answers in barely intelligible English", then their contributions are not going to uphold the standards of posts on the SE network; that the questions are clear, show research effort, and are answerable within the scope of the site.
Also you're making an assumption which is not necessarily true: that because a user posts a question in less-than-stellar English, they have questions about the English language that they want answered. If I had a programming question and the site with the answer to my programming question was in Klingon, I'd be very upset if the response to my broken-Klingon programming question was the suggestion to go to another site to ask questions about the Klingon language. It just doesn't really make sense.
We do refer users to ELL when they post good-quality questions to EL&U which seem like they are more appropriate for ELL. But that's not nearly the same thing as purposefully seeking out bad questions that are posted by non-native speakers and referring them to ELL for that reason. If the question is bad, close it. That's what the system is for. But don't intentionally send a user with a bad question-asking track record to another SE site. That isn't good for anyone. (Try educating them about SE instead?)