A friend from Central America was reading a Montréal newspaper article and came across an expression he didn’t know:
C’est-y pas beau?
He asked what this expression means and what the y is doing in there.
Here’s an example context (that I’ve made up) of how the expression was used:
Le gouvernement va augmenter la taxe sur l’essence. C’est-y pas beau, ça?
The government is going to increase tax on gas. Well ain’t that nice?
Can you guess now what that y means? It means the exact same thing as tu when used informally to create a yes-no question.
C’est vraiment necessaire.
C’est-tu vraiment necessaire?
It’s really necessary.
Is it really necessary?
C’est ben cher.
C’est-tu ben cher?
It’s really expensive.
Is it really expensive?
Y and tu, when used to create informal yes-no questions, are variants of one another.
The question c’est-y pas beau? contains sarcasm. The person asking this question dislikes the situation it refers to and is using the question to highlight this fact.