Columbia subject headings:
Harvard subject headings:
German language--Dialects--Germany--Congresses.
Linguistic minorities--Germany--Congresses.
Princeton subject headings:
Danish language--Germany--Congresses.
Frisian language--Germany--Congresses.
Languages in contact--Germany--Congresses.
Linguistic minorities--Germany--Congresses.
Low German language--Congresses.
Sorbian languages--Germany--Congresses.