Cybertronian Sign Language

Cybertronian Sign Language is a form of communication utilizing hand gestures and body language that allows Transformers who have lost the ability to speak or hear a means of communicating with their fellow 'bots. It's not a language for a 'bot in a hurry, but when the chips are down it allows them to get the point across.

"Guilty as Charged"
When the Bee Team, mistakingly believing he was an escapee from Trypticon Prison, trapped Blastwave in a force-cell, he used Cybertronian Sign Language to communicate to the shocked Autobots that he was in fact the bounty hunter his quarry, Nightra, had claimed to be. Bumblebee, having previously suffered voicebox loss himself, immediately recognised the gestures.