Columbia subject headings:
Harvard subject headings:
Borderlands
Language planning
Language policy
Language services
Language spread
Languages in contact
Linguistic geography
Sociolinguistics--Cross-cultural studies.
Princeton subject headings:
Borderlands.
Language planning.
Language policy.
Language services.
Language spread.
Languages in contact.
Linguistic change.
Linguistic geography.
Sociolinguistics--Cross-cultural studies.