six

Inherited from Middle French six, from Old French sis, six, from Latin sex, from Proto-Indo-European *swéḱs. The numbers six and dix (“ten”), as well as the pronoun tous (“all”), are remnants of the Old and Middle French pronunciation system where final -s or -x was silent before consonants, pronounced /z/ before vowels, and /s/ in pausa. The only change is that the pausal pronunciation is now invariably used when these words do not precede their referent.