Tag misuse, particularly with tags with
chinese in them, seems to have been a common issue. This presumbly is a result of new users erroneously tagging questions with simplified-chinese solely because they're using simplified characters (which is rather inappropriate except for issues related to reading / writing). This also has happened in the past with tags with
learning in them -- users presumably add such tags solely because they happen to be learning Chinese.
Similarly, some other tags appear to be duplicates but haven't been very well taken care of in the past. Tag descriptions should also be added in those cases, as it is rather unclear in some cases what tags actually cover and there appears to be overlap (e.g. with learning, learning-chinese, language-learning, and academic).
Unless such tags are pertinent to the question, all they do is create "noise" for questions that are legitimately focused on these topics. An analogy: it would be bad if I used windows on SO solely because it was the OS I was using to write my code. (To boot, the Windows tag on SO specifically states that it is only for Windows-specific problems.) Moreover, having multiple tags that essentially cover the same material makes it difficult to locate questions on a topic, because often, people will not be aware of all the relevant tags when they search for content.
I fixed most of the blatantly incorrect cases, but there should be clarification on what these tags are for via use of the tag descriptions (which the last time I checked were non-existent), particularly since I can't tell if I've simply misunderstood the purpose of the tags. As such, we should clarify when which tags should be used, and also synonymize / delete tags if necessary. I am using this meta post as a place to point out the issues I have spotted, and other users are welcome to add to it. I do not want to fix everything by myself without any discussion, as it is possible that I am simply unaware of community consensus on tag usage.
Edit: I am going to add tag specific issues (as grouped under what the "main" issue is) as answers, since this post is becoming extremely unwieldy. I will also add my opinion of what the best approach is, in the cases where I have one.