Most communication in games takes place verbally. But this does not need to be the case. Set up a non-verbal gesture language with your fellow party members and you can convey messages in absolute silence while sneaking through a hobgoblin lair. Or agree on code signals flashed with lights. If you have a language slot free on your character sheet, go for something like sign language - it's going to be more useful than being able to speak bugbear or some other obscure monster language that you'll probably never need to use.

GMs: If your players go for this... um, well, actually it's not a bad idea. But maybe you could throw more bugbears at them or something. With shamans who can cast Darkness spells.

Transcript

Han: Okay, wait, I have a better idea.
[SFX]: Tuuurnn...
[SFX]: Pow!
C-3PO: What are you doing? Running away is that way!
Captain Needa: Attention, small cargo vessel, where'd you learn to fly? The Kessel Run?
Captain Needa: You utter moron! You better not be trying to ram us.
Captain Needa: If there's a single scratch on our paintwork, and you somehow survive, your ass will be a hood ornament!
[SFX]: Whoooossh!
Captain Needa: Space hog!
Unidentified Imperial officer: Uh, sir, you realise they can't see that gesture you're making out the window?
C-3PO: Oh yeah? I'm fluent in over six million offensive gestures, and I'm making all of them in your general direction!