Insular Celtic languages are the group of Celtic languages spoken in Brittany, Great Britain, Ireland, and the Isle of Man. All surviving Celtic languages are in the Insular group, including Breton, which is spoken on continental Europe in Brittany, France. The Continental Celtic languages, although once widely spoken in mainland Europe and in Anatolia, are extinct.
Six Insular Celtic languages are extant (in all cases written and spoken) in two distinct groups:
Manx (endonym: Gaelg, y Ghaelg or Gailck, y Ghailck, pronounced [ɡilʲkʲ, ə ˈɣilʲkʲ]),also known as Manx Gaelic, is a Gaelic language of the insular Celtic branch of the Celtic language family, itself a branch of the Indo-European language family. Manx is the heritage language of the Manx people.
Although few children native to the Isle of Man speak Manx as a first language, there has been a steady increase in the number of speakers since 1974, when Ned Maddrell, considered the last speaker to grow up in a Manx-speaking community environment, died. Despite this, the language has never fallen completely out of use, with a minority having some knowledge of it as a heritage language, and it is still an important part of the island's culture and cultural heritage.
Neo-Brittonic, also known as Neo-Brythonic, is a stage of the Insular Celtic Brittonic languages that emerged by the middle of the sixth century CE. Neo-Brittonic languages include Old, Middle and Modern Welsh, Cornish, and Breton, as well as Cumbric (and potentially Pictish).
The Gallo-Brittonic languages, also known as the P-Celtic languages, are a proposed subdivision of the Celtic languages containing the languages of Ancient Gaul (both Celtica and Belgica) and Celtic Britain, which share certain features. Besides common linguistic innovations, speakers of these languages shared cultural features and history. The cultural aspects are commonality of art styles and worship of similar gods. Coinage just prior to the British Roman Period was also similar. In Julius Caesar's time, the Atrebates held land on both sides of the English Channel.
It contrasts with the Insular Celtic hypothesis, which asserts that Goidelic and Brythonic underwent a period of common development and have shared innovations to the exclusion of Gaulish, while the shared changes are either independent innovations that occurred separately in Brythonic and Gaulish or are due to language contact between the two groups.