Invented a sort of Celtic shorthand called the Ogham Runes. These are mostly symbols for various trees, and apart from engravings on funeral stones and the like, remain somewhat mysterious.
It seems the Ogham Runes were used by druidic types for divination and possibly solving early cross-word puzzles. So no-one in this day-and-age knows quite what he was trying to say. Probably blarney.
His ears are chained to his tongue, which seems rather masochistic, but we are told it is to signify in some bizarre way that he is the God of Eloquence. Or maybe he is just tongue-tied. Or likes talking to himself.
We consider that nowadays he must also be the God of Cell Phones and Blogging. He ought to be the mascot of all self-respecting Tweeters and Facebookers. Especially the Celtic ones.
The Gaulish version seems to be OGMIOS.