Columbia subject headings:
Celtic languages--Political aspects.
Celtic languages--Religious aspects.
Celtic languages--Social aspects.
Harvard subject headings:
Celtic languages--History.
Celtic languages--Political aspects.
Celtic languages--Religious aspects.
Celtic languages--Social aspects.
Language and culture--Ireland--History.
Language and culture--Scotland--History.
Language and culture--Wales--History.
Princeton subject headings:
Celtic languages.
Language and culture--Ireland.
Language and culture--Scotland.
Language and culture--Wales.