We're not sure if anyone has ever used "Tally-ho!" in real life. Which makes it a perfect phrase to use in game circumstances.

Build up a collection of words, phrases, and idioms that you and the people you associate with never use, but that sound cool. Keep them in a notebook or something if you have to. And use them in your games when playing a character. It gives the character a definite sense of being someone else, and helps you get into that character, rather than just being a proxy of yourself in the game.

If you think of a cool and unusual phrase during a game, try writing it on your character sheet and have your character repeat it every now and then. If you do this, you can build up a half dozen or so unique turns of speech for each character you play, to make them truly unique and memorable.

Transcript

R2-D2: If you get rid of paper, rock is definitely overpowered.
C-3PO: But what do you use to write down stuff?
Kermit: Much more reliable storage systems.
Kermit: Memory marbles.
GM: Luke, your searching leads you into the middle of this conversation.
Luke: Aha! Yoda! Yoda!
Kermit: Hmmm?
Luke: Have you seen Yoda?
Kermit: Seen Yoda I have not. But most other people here have.
Luke: Right. Well I better go talk to them then. Tally-ho!
{Luke runs off upstairs to a dressing room}
R2-D2: Do you think he's actually stupid or just roleplaying stupid?
C-3PO: He's learnt a lot from Jim.
R2-D2: My question stands.