Translation:There is a huge number of languages in the world.
Even as a native speaker of English, I get confused with this one: isn't it supposed to be "There are a huge number of..."?
It sounds a lot better that way, in my opinion
Well, technically, it's singular, because the verb-noun agreement should be with "number", not "languages". So I think the correction is incorrect. ;)
I think this is similar to the debate I had in Russian about "there are a lot of mountains" vs. "there is a lot of mountains". Even though you can make a good grammatical argument either way since "a lot" is singular, the latter sentence sounds very weird, and a Google search suggests that "there are a lot" is used as much as 15 times as frequently.
You are correct for American English. The rule now is that if the indefinite article is used ("a number of"), then it is an adjective phrase and the following noun ("languages" in this case) controls the number of the verb, i.e., a plural verb form. On the other hand, if the definite article is used ("the number of"), then "number" controls the verb.
There are a huge number of languages in the world. This is grammatically equivalent to "there are enormously many languages in the world." Although many languages are unfortunately disappearing, the number of languages in the world is still very large.