The Celtic or Keltic languages (usually pronounced /ˈkɛltɪk/ but sometimes /ˈsɛltɪk/) are descended from Proto-Celtic, or "Common Celtic"; a branch of the greater Indo-European language family. The term "Celtic" was first used to describe this language group by Edward Lhuyd in 1707.
Celtic languages are most commonly spoken on the north-western edge of Europe, notably in Ireland, Scotland, Wales, Brittany, Cornwall, and theIsle of Man, and can be found spoken on Cape Breton Island. There are also a substantial number of Welsh speakers in the Patagonia area of Argentina. Some people speak Celtic languages in the other Celtic diaspora areas of the United States, Canada, Australia, and New Zealand. In all these areas, the Celtic languages are now only spoken by minorities though there are continuing efforts at revitalization.
During the 1st millennium BC, they were spoken across Europe, in the Iberian Peninsula, from the Atlantic and North Sea coastlines, up the Rhinevalley and down the Danube valley to the Black Sea, the Upper Balkan Peninsula, and in Galatia in Asia Minor. The spread to Cape Breton and Patagonia occurred in modern times. Celtic languages, particularly Irish, were spoken in Australia before federation in 1901 and are still used there to some extent.