firstlanguage

First language, commonly abbreviated L1, refers to the language a person learns first, typically the language spoken at home during early childhood. It is often considered the native language or mother tongue and is distinct from a second language (L2), which is learned later through schooling or other exposure. First language acquisition is the process by which young children acquire phonology, vocabulary, syntax, and pragmatic use of their L1 through natural social interaction.

In typical development, children progress through stages of language growth that begin with preverbal communication, move to babbling, then early one-word and two-word utterances, and eventually more complex sentences. While most children acquire their L1 with relative speed and ease, there is substantial variation across languages, cultures, and individual circumstances. Exposure, motivation, and the linguistic complexity of the input influence outcomes.

For bilingual or multilingual individuals, the status of L1 can be fluid. A person may maintain strong proficiency in an L1 while acquiring additional languages, or dominance may shift with changing exposure and use. The term first language can also intersect with identity and sociolinguistic factors; some prefer terms like home language or heritage language in certain contexts.

In education and policy, recognizing a child’s L1 can support literacy and learning in L2 by leveraging existing linguistic knowledge. Researchers study first language acquisition to identify universal patterns and language-specific variation, while examining how social environment, cognitive development, and exposure shape early language growth.