Columbia subject headings:
Diglossia (Linguistics)--Congresses.
Sociolinguistics--Congresses.
Harvard subject headings:
Diglossia (Linguistics)--Congresses.
Language and languages--Variation--Congresses
Sociolinguistics--Congresses.
Princeton subject headings:
Diglossia (Linguistics)--Congresses.
Sociolinguistics--Congresses.