The Irish language is known to be a part of the Indo European family. There are a few other languages in the group that are similar to Irish in more than one way. The group of these Indo European languages is known as the Celtic languages. Edward Lhuyd had coined the term Celtic in 1707 to describe these languages. Ireland, Scotland, Cornwall, Isle of Man, Wales and Brittany are the countries were these Celtic languages are spoken. The list of these languages includes Irish in Ireland, Scottish Gaelic in Scotland, Manx in the Isle of Man, Welsh in Wales, Cornish in Cornwall and Breton in Brittany. Irish, Scottish, and Manx form the group of Goidelic languages and are still in use today. While Welsh, Cornish, and Breton form another group of languages called the Brythonic languages. Cornish out of these had become extinct in the 18th century but of late has been revived again. There are similarities in the languages of a particular group but not in between the groups.

Scottish Gaelic: Except for the Northern Islands the language was spoken all over Scotland in the past. But gradually in the later part of the middle ages, it was English that had gained prominence. With the union of England and Scotland, the language was majorly looked down upon and the English language had completely taken over. Today there is only a minority of the population that speaks the language.

Manx: Spoken in the Isle of Man the language belongs to the family of Scottish and Irish. It is a protected language under the European Charter for Regional or Minority Languages. During the 19th century, there has been a gradual decline in the Manx speakers with the last of the old native speakers dying in 1974. Today the language is taught only in 5 preschools in the Isle of Man.

Welsh: It is the national language of Wales and is still spoken throughout the region. Even though English has gained prominence over the years the Welsh language is still an important part of there culture. Schools in Wales have the language as a compulsory subject.

Breton: It is spoken in Brittany in the northwest of France and has close resemblances to the Cornish language. There are about 240,000 speakers, who use the language but the number is declining due to the French government laying emphasis on the use of French.

Cornish: This is one of the oldest languages spoken in Cornwall. But the number of speakers of the Cornish language saw a gradual decline with the growing prominence of English. The Cornish language has a good amount of similarity to Welsh.