'aren't' is a contraction of 'are not.' It functions as a verb, specifically the negative form of the verb 'are' in the present tense.
'aren't' is used with plural subjects and the singular pronoun 'you.' It can be used in questions, negative statements, and negative tag questions.
Aren't you coming to the party tonight?
They aren't ready for the test.
It's a beautiful day, aren't they lucky?
a common mistake is using 'aren't' with singular subjects other than 'you.' For example, 'He aren't coming' is incorrect; the correct form is 'He isn't coming.' In informal spoken English, some people use 'aren't' in tag questions with 'I,' as in 'I'm next, aren't I?' Although this is widely understood and accepted in casual conversation, it's considered non-standard. The more formal alternative is 'am I not.'