Once Celtic languages were widely spoken throughout Europe and even in parts of Asia Minor. Now some of them are extinct since a long time and those, that are still present, are endangered very much. There are prognosis that they will disappear by the end of the 21st century. There are six Celtic languages that are still spoken, although not widely. These are: Irish, Scottish, Manx, Welsh, Cornish and Breton. The first three belong to the group of the Celtic languages know as Q-Celtic or Gaelic (Goidelic). It is important to add ‘Gaelic’ when speaking about Scottish, as just ‘Scottish’ refers to the branch of Germanic languages. The second group is called P-Celtic or Brittonic (Brythonic). To this group belong three other listed languages. Among these six languages Cornish is a new construct that appeared in the 20th century. Irish is the only Celtic language that is spoken in an independent country, however, the biggest number of speakers has Welsh. The Author of this article describes each of the existing Celtic languages, presenting briefly its history, coming up to its decline, then to a turning point - revival movements, ending up with their present situation.