In a scene from Les Parent, Natalie asks the other members of her family if they’re ready to leave. She does this by asking: On y va-tu? “Ready to go?”
The –tu here is an informal yes-no question word. It doesn’t mean “you” as you may have expected. On y va-tu is an informal way of saying est-ce qu’on y va.
The informal yes-no question word -tu occurs in spoken, informal French. In writing, it only appears in informal texts, like comic strips or text messages, or in some forms of literature where a character’s informal speech is being portrayed.
Another example:
C’est-tu clair? (informal)
= Est-ce que c’est clair?
Even when speaking informally, you can always use est-ce que. Do learn to recognise this use of -tu, though.
[This entry was inspired by the character Natalie in Les Parent, “Blues d’automne,” season 3, episode 7, Radio-Canada, Montreal, 25 October 2010.]