P-Celtic and Q-Celtic languages
However, it is controversial in the research, the extent to which the division of the Celtic languages in p- Celtic and q- Celtic languages is really useful. On one hand, the phonological difference between / kw / and / q / and / p / rather low, on the other hand would reach in this way the Goidelic languages, celtiberian in the narrow group of q- Celtic languages . But otherwise widely These languages differ. The p- Celtic languages are compared to each other somewhat more homogeneous. Therefore may be other criteria such as the geographical distribution or the inclination to start mutations for a fundamental division of the Celtic languages are more suitable.