I've recently noticed that there are often a lot of questions regarding R that aren't tagged with R. Many of these questions do not have any answers/comments/votes. This seems to be bad both for the question askers (who didn't get any help) and for the site (since it leaves a bunch of dangling questions that won't help future people who stumble across them).
So, I've been going through and tagging some of these questions R. After doing this for a while, I realized others might consider this annoying because it bumps old questions (potentially where the askers aren't around any more) up the "Active" queue. I also read this question on meta, where the consensus seems to be that all questions should have language tags.
My question: What's best practice here? Is it good to add language tags to questions that probably haven't been answered because nobody with the right language expertise saw them? Or is it better to flag them for closure? Is there some threshold of time after which one practice should be favored instead of the other?