Proto-Celtic

The Proto-Celtic language, also called Common Celtic, is the putative ancestor of all the known Celtic languages. Probably spoken around 800 BC, its lexis can be confidently reconstructed on the basis of the comparative method of historical linguistics. Proto-Celtic is a direct daughter-language of Proto-Indo-European and is widely regarded as the first of the Indo-European languages to spread in northwestern and Atlantic Europe. The area in which the language seems to have first become distinguishably Proto-Celtic, as opposed to an earlier Centum dialect, corresponds to the Hallstatt culture, on the western fringes of the  Urnfield.
See more at Wikipedia.org...