"tu" is sometimes used in a different way in the French of Quebec.

-tu can be tacked on to the end of a verb to form yes-no questions, similar to est-ce que. So:

C'est-tu possible ?
Est-ce que possible ?
Is this possible?

Pronounced [tsy], the particle -tu is not directly related to the pronoun. Some regional languages and dialects of France (like Norman) use -ti or -i to indicate questions in the same way. It is more likely that the change of vowel is due to influence from the pronoun, rather than direct relation. Indeed, -tu can be used together with the pronoun tu (tu comprends-tu ?).

-tu is not used with question works like quand, comment, pourquoi, qui..., because these are not yes-no questions.