Gaelic vs Celtic
Generally speaking, Gaelic, also known as Scottish Gaelic, is one of the Celtic languages that belong to the Goidelic branch, and it is a native language in Scotland. Other Gaelic languages that belong to the Goidelic branch are Manx and Irish, which, together with Scottish Gaelic, originated from old Irish. However, Manx is no longer being spoken, and according to some accounts, the last person to use the language died in 1962; although there’s no consensus on this. Another branch of the Celtic language is the Brythonic branch, which is different from, and larger than, Goidelic. It includes Breton, Welsh and Cornish.
Other Celtic language families include Gaulish, which is closely related to Lepontic, Galatian and Noric, which are all now extinct. Another family is the Celtiberian, which was, in the ancient times, a native language in the Iberian Peninsula, which is the present day northern Portugal, parts of Leon in Spain, Galacia and Aragon.
The Celts (or Celtics) were a well-known group of people, with a specific culture, who lived in Western Europe. Originally, they occupied southern Poland, Austria, Germany and Czechoslovakia, but were driven out of central Europe by their neighbors, the Germanic tribes. Their Celtic languages originated with the Common Celtic (also called Proto-Celtic), which is a branch of the Indo-European languages.
Currently, Celtic languages are not that widely spoken, and they are limited to selected places in Western Europe, particularly Ireland, places in Great Britain, including Wales, Cornwall and Scotland, and France’s peninsula of Brittany, Patagonia, Cape Breton Island and the Isle of Man. It’s worth noting, that in modern times, Celtic languages are only spoken by minority communities, although revival efforts have also regained momentum. In Australia, where it was spoken before the federation in 1901, is now also extinct.
Scholars handling the subject of Celtic languages have never consented to the true origins of these languages; a situation made worse by the lack of original data sources. Some argue that Continental Celtic and Insular Celtic are different, stating that the split of the Goidelic and Brythonic languages from Continental Celtic caused the differences.
Summary:
Gaelic is a language, whereas, Celtic was a group of people with a specific culture that used the Celtic languages.
Gaelic is a ‘subset’ of the Celtic languages, specifically belonging to the Goidelic family of Celtic languages.