Mezygmy Hand Sign

The tiny humanoids of the Mezygmy Jungle originally came from the prison plane of the Hungry Dark, and were created without vocal cords to keep them from being traditional casters. They have overcome this with a language built around facial expressions and hand signs, and Mezygmy casters are able to do most any spells using a hand motion in place of a spoken word.
Mezygmy Hand Sign is included in the Gether Guide to Languages on DrivethruRPG:
https://www.drivethrurpg.com/product/328473/Gether-Guide-To-Languages