A colloquial form of "isn't" used mostly in the southern United States.
Tiny: The movie's showing at 7:30, itn't it?
Kiko: What are you talking about? What movie?
Tiny: Galaxy Quest 2
Kiko: Oh, Tiny!
Tiny: Never girve up, never surrender! Hoo hoo *spreads arms and runs while making plane sounds*
Kiko: Sai saichi!