COMMENT: One of the most reliable comparisons put forward by Trubetzkoy (1930,277); see also Abdokov 1983, 85. Despite some authors (Dzhavakhishvili 1937,419, Bghazhba 1948,42, Klimov 1963,223) this root has nothing to do with the PNC numeral "one" q.v.
The only apparent irregularity is the strength of *c: in PWC, while the PEC root vowel is short. This is probably due to the early vowel contraction after the (regular) loss of resonant+laryngeal in PWC.
