ask: *vo-gen-, root gen, know, as in aithne. Cf. Early Irish imma foacht, asked. Windisch refers to iar-faigim, iarfacht, I asked, = iarmifoacht, root ag, say. iarmi-fo-siag (St. R.C.$$+19 177).
Etymological dictionary of the Gaelic language.
Alexander Gairm Publications.
1982.