He argued that the Brythonic languages originated in Gaul (France), and that the Goidelic languages originated in the Iberian Peninsula.
Gaelic first names chiefly hail from 5 linguistic layers, Goidelic and 4 others, coinciding with the main languages of contact: Latin, Norse, Anglo-Norman and Scots.
Goidelic roots accounts for most place-names in eastern Scotland, with a few Anglic names in Fife and Angus and with a small number Pictish elements assimilated into the total toponymy.