Consonants[]
The following consonants have been reconstructed for Proto-Celtic:
| Type | Bilabial | Alveolar | Palatal | Velar | |||||
|---|---|---|---|---|---|---|---|---|---|
| plain | labialised | ||||||||
| Plosive | p | b | t | d | ɟ | k | ɡ | kʷ | ɡʷ |
| Nasal | m | n | ɲ | ŋ | ŋʷ | ||||
| Fricative | ɸ | β | s | z | ʝ | x | ɣ | xʷ | ɣʷ |
| Approximant | l | j | ɰ | w | |||||
| Trill | ʙ | r | |||||||
Vowels[]
The Proto-Celtic vowel system is highly comparable to that reconstructed for Proto-Indo-European by Antoine Meillet. The following monophthongs have been reconstructed:
Type Front Central Back unr. rnd. unr. rnd. unr. rnd. long short long short long short Close iː i y ɯ uː u Close-mid e ø ɘ ɤ o Open-mid ɛː ɛ œ ʌ ɔː ɔ Open æ aː a ɶ ɑ ɒ
The following diphthongs have also been reconstructed:
| Type | With -i | With -u |
|---|---|---|
| With e- | ei | |
| With a- | ai | au |
| With o- | oi | ou |