French is today the official language of Brittany.

Breton (Ar brezhoneg) is a Celtic language similar to Cornish, Welsh, Irish or Scottish Gaelic. It is mainly spoken in western Brittany and is currently experiencing a rebirth after years of suppression. Gallo, a Roman language, is spoken in eastern Brittany. It is common to see road signs in Brittany in two languages.

If the bilingual school population and adult speakers are combined, there are nearly 270,000 active Breton speakers in Brittany. This means that 6.7% of the population of Brittany regularly speaks Breton to those around them (spouses,family, friends, colleagues, shop staff, teachers).

The Breton language - CNN

The Breton language - Al Jazeera