Sociolinguistics is the study of the relationship between language and society. It examines how factors like region, social status, and ethnicity can impact language use between groups and individuals. Code-switching occurs when speakers fluidly switch between two or more languages or language varieties during conversation. Code-mixing is similar but involves integrating elements of other languages into sentences. Sociolinguistic concepts like diglossia, bilingualism, and language interference help explain language variation and use within multilingual communities and societies.