Related to the word "Later" used by the 'cool kids' to say good-bye.
the word "Lata" comes from a partially deaf teen who will also roll his eyes back and throw up one finger in the air. Its his partially-deaf way of saying see ya around.
Those who can hear: Okay well ill see you later!
Those who can't: Okay lata.
When annoying kids on counter strike get a kill and they think it was good they usually scream "LAAAAAATTTAAAAAAAA" in the mic making ur ears bleed. People also use it to annoy other ppl when they kill them to make them feel bad at the game.