One problem is, is it being used as an adjective or a noun in this example? I think adjective, and hence it is most naturally a descriptor.

But it could also be a noun as you pointed out. WordNet lists four nominal senses:

1. English, English language — (an Indo-European language belonging to the West Germanic branch; the official language of Britain and the United States and most of the Commonwealth countries)
2. English, English people, the English — (the people of England)
3. English — (the discipline that studies the English language and literature)
4. English, side — ((sports) the spin given to a ball by striking it on one side or releasing it with a sharp twist)

Of course each of these is a valid interpretation in some context, and we probably won’t be able to resolve which is the appropriate one for a tag. But here is an interesting observation, if you look at the grammatical properties of the words. They are all mass nouns (or proper noun in some case) … so none of them are about individuated countable “things”. So in an ontological sense none of the interpretations would qualify as a “thing”.

the same word end up having different meaning in different context. So ‘english’ means that a post is in english or that it is about the english language. It would work if we were using latin or maybe german.

P.