|Formerly widespread in much of Europe and central Anatolia; today Cornwall, Wales, Scotland, Ireland, Brittany, the Isle of Man, Chubut Province, and Nova Scotia|
|ISO 639-2 / 5||cel|
Eska (2010) evaluates the evidence as supporting the following tree, based on  evaluates the evidence as supporting the following tree, based on shared innovations, though it is not always clear that the innovations are not areal features. It seems likely that Celtiberian split off before Cisalpine Celtic, but the evidence for this is not robust. On the other hand, the unity of Gaulish, Goidelic, and Brittonic is reasonably secure. Schumacher (2004, p. 86) had already cautiously considered this grouping to be likely genetic, based, among others, on the shared reformation of the sentence-initial, fully inflecting relative pronoun *i̯os, *i̯ā, *i̯od into an uninflected enclitic particle. Eska sees Cisalpine Gaulish as more akin to Lepontic than to Transalpine Gaulish.