Celtic languages are a branch of the Indo-European language family primarily spoken in the British Isles and parts of Brittany in France. They are divided into two main groups: Goidelic (or Gaelic), which includes Irish, Scottish Gaelic, and Manx, and Brythonic (or Brittonic), which includes Welsh, Cornish, and Breton. These languages share common historical roots and have distinct characteristics, such as unique phonetics and vocabulary. While their number of speakers has declined over the years, efforts are ongoing to preserve and revitalize them, particularly in regions where they are traditionally spoken.