The weather is hot, isn’t it?
The weather is hot, is it not?
Aren’t you going to study tonight?
Are you not going to study tonight?
Apart from convenience in pronuncation, how do the above versions differ (contraction vs. full form)?
It’s just extremely common to see tag questions that use contractions as opposed to their uncontracted forms.
A COCA search for
, _v* * * ? (comma, verb, two words, and a question mark; note that “n’t” is considered a separate word) shows that “isn’t it?“ is much more common (5395 hits) than “is it not?” (334 hits).
Still, 334 hits is not insignificant. There’s nothing wrong grammatically with the uncontracted form. It (in general as well) is just more emphatic and sounds more formal.