Columbia subject headings:
Duala language--Grammar.
Duala language--Textbooks for foreign speakers--French.
Harvard subject headings:
Cameroon--Languages.
Duala language--Textbooks for foreign speakers--French.
Duala language.
Princeton subject headings:
Duala language--Glossaries, vocabularies, etc.
Duala language--Grammar.
Duala language--Textbooks for foreign speakers--French.