Columbia subject headings:
Harvard subject headings:
Europe--Languages--History--Congresses.
Language and languages--Etymology--Congresses.
Language and languages--Origin--Congresses
Language and languages--Variation--Congresses
Language policy--Europe--Congresses.
Languages in contact--Europe--Congresses.
Linguistic change--Europe--Congresses.
Princeton subject headings:
Europe--Languages--History--Congresses.
Language and languages--Origin--Congresses.
Languages in contact--Europe--Congresses.