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

Trade, migration, conquest, and digital media create contact 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 what can transfer between systems. Historical linguistics relies on contact evidence to explain unexpected similarities. Education and official-language policy 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