The Celtic languages are divided into two main branches: Goidelic (or Gaelic) and Brythonic (or Brittonic). Here is a list of all the known and recorded Celtic languages, both historical and living:
Goidelic (Gaelic) Branch:
Old Irish (c. 6th to 10th centuries CE) – The earliest form of the Irish language, from which modern Irish, Scottish Gaelic, and Manx developed.
Middle Irish (c. 10th to 12th centuries CE) – Transitional phase between Old Irish and the modern Goidelic languages.
Irish Gaelic (Gaeilge) – A living language spoken primarily in Ireland, with three main dialects: Munster, Connacht, and Ulster.
Scottish Gaelic (Gàidhlig) – A living language spoken primarily in the Highlands and Islands of Scotland.
Manx (Gaelg) – Historically spoken on the Isle of Man, Manx became extinct as a native language in the 20th century but has been revived and is now spoken by a small community.
Brythonic (Brittonic) Branch:
Common Brittonic (or Brythonic) – The ancestor of the modern Brythonic languages, spoken in Britain before and during the Roman occupation.
Old Welsh (c. 6th to 9th centuries CE) – The earliest recorded form of Welsh.
Middle Welsh (c. 12th to 14th centuries CE) – Transitional phase between Old Welsh and modern Welsh.
Welsh (Cymraeg) – A living language spoken primarily in Wales, with two main dialects: North and South Welsh.
Cornish (Kernewek) – Spoken historically in Cornwall, it became extinct in the 18th century but has been revived, with a small number of speakers today.
Breton (Brezhoneg) – A living language spoken in Brittany, France. It is the only Brythonic language still spoken on the European mainland.
Extinct and Lesser-Known Celtic Languages:
Gaulish – Spoken in what is now France and surrounding areas during the Iron Age and Roman period. It was mostly replaced by Latin after the Roman conquest.
Lepontic – Spoken in northern Italy and southern Switzerland during the Iron Age, closely related to Gaulish.
Celtiberian – Spoken in the Iberian Peninsula (modern-day Spain) by Celtic tribes, especially in central and northeastern regions.
Gallaecian – Spoken in the northwest of the Iberian Peninsula, closely related to Celtiberian and influenced by Lusitanian.
Pictish – Spoken in Scotland by the Picts, believed to have been a Brythonic language, though it remains poorly understood.
Cumbric – Spoken in what is now southern Scotland and northern England (Strathclyde and Cumbria), closely related to Welsh. It is believed to have become extinct by the 12th century.
These languages represent the rich and diverse linguistic heritage of the Celtic peoples, with a few still actively spoken and others that are subjects of linguistic study and revival efforts.