Even if Raetian was the ancestral language of the Raeti, there is considerable uncertainty as to how widely Raetian was spoken among the tribes by the time of Augustus (ruled 30 BC - AD 14). In the Alpine region as a whole, there is evidence that the non-Celtic elements had, by the time of Augustus, been assimilated by the influx of Celtic tribes and had adopted Celtic speech. According to Livy, the sound of the Raeti's original Etruscan tongue (sonum linguae) had become corrupted as a result of inhabiting the Alps. This may indicate that at least some of the tribes lost their ancestral Raetic tongue to Celtic. Celticisation also finds support in the Roman practice of twinning the Raeti with their neighbours to the North, the Vindelici, who are regarded by most historians to have been Celtic- speakers. The territories of the two peoples were combined for administrative purposes from an early stage and eventually, under the emperor Claudius (ruled 41-54), as the province of Raetia et Vindelicia. In addition, a pair of joint Raetorum et Vindelicorum auxiliary cohorts were established under Augustus.