The six modern-day Celtic nations — often referred to as the “home countries" — are Scotland (Alba), Brittany (Breizh), Wales (Cymru), Ireland (Eire), Cornwall (Kernow), and the Isle of Mann (Mannin). Sometimes disparagingly termed the “Celtic Fringe” of the so-called “British Isles,” these six nations are a group defined by common bonds of culture, history, and above all, language.

Language is at the heart of the Celtic League’s definition of Celtic nationhood. Though several other nations and regions can claim a Celtic cultural or historic heritage (notably Galicia and Asturias in northwest Iberia,) the Celtic League adheres to a linguistic definition of Celtic nationality. In short, a Celtic language defines a nation as Celtic. Each of the six Celtic nations possesses its own distinct Celtic language that is spoken by at least some part of its citizens.