Professor Rhys takes this very name Glasgow as illustrative of the spread of the Goidelic as against the Brythonic Pictish idioms.  Thus in his work on Celtic Britain (p. 195), to which I am greatly indebted, he says—"Next may be mentioned the name of Kentigern, which would be pronounced by his kinsmen in his time Cunotigernos, or the like, in the first part of which the Goidels discerned the word for hound, and called the saint In Glas Chú, or the grey hound; so though he was a Brython, and the place he settled at finally was in the land of the Cumbrians, it is now known only by his Goidelic name as Glasgow." (Transactions of the Glasgow Archaeological Society, v.2, 1883)