When speakers of different languages meet, their systems influence each other. Language contact is the interaction between linguistic communities that leads to borrowing, structural convergence, code-switching, and sometimes new contact varieties.

Trade, migration, conquest, and digital media create contact situations of varying intensity. Outcomes range from a few loanwords to heavy structural borrowing or language shift. Prestige imbalances shape which language gives and which takes.

Contact linguistics documents these processes and tests theories of what can transfer between systems. Historical linguistics relies on contact evidence to explain unexpected similarities. Policy decisions about education and official languages often respond to long-standing contact zones.

• Interaction between different language communities
• Produces borrowing, switching, and new varieties
• Driven by trade, migration, and power relations
• Key to explaining many historical changes