Proto-Indo-European phonology has been reconstructed in some detail. Notable features of the most widely accepted (but not uncontroversial) reconstruction include: three series of stop consonants reconstructed as voiceless, voiced, and breathy voiced; sonorant consonants that could be used syllabically;

This article contains characters used to write reconstructed Proto-Indo-European words (for an explanation of the notation, see Proto-Indo-European phonology). Without proper rendering support, you may see question marks, boxes, or other symbols instead of Unicode combining characters and Latin characters.

Celtic languages, also spelled Keltic, branch of the Indo-European language family, spoken throughout much of Western Europe in Roman and pre-Roman times and currently known chiefly in the British Isles and in the Brittany peninsula of northwestern France. On both geographic and chronological grounds, the languages fall into two divisions, usually known as Continental …