Language is a structured system of conventional signs through which people communicate, express thought, and coordinate social activity. The term refers both to the human capacity for language and to particular languages used by communities. Languages may be spoken, signed, or represented in writing. They are central to culture and are studied scientifically by linguistics. Natural sign languages are complete languages with their own grammatical systems, while a writing system represents aspects of language rather than constituting a prerequisite for it.
Structure and meaning
Language operates through interacting levels of organization. Phonetics examines the production, physical properties, and perception of speech sounds. Phonology studies how languages organize contrastive units and patterns; in signed languages, these include handshape, location, movement, and other articulatory features.
Morphology concerns the internal structure of words, including roots and affixes. Syntax examines how words and other units combine into phrases and sentences. Together, these are major components of grammar, although the term can also encompass a language’s broader structural system. Languages differ in how they distribute information across word order, inflection, particles, and context.
Semantics studies conventional meaning, including meanings associated with words and their combinations. Pragmatics investigates interpretation in context: what speakers intend, what listeners infer, and how shared knowledge affects understanding. For example, “It is cold here” can state a temperature condition or indirectly request that a window be closed.
These levels are analytically distinguishable but interact continuously. Intonation can change an utterance’s interpretation, and grammatical structure can resolve or create ambiguity.
Distinctive properties
Human languages are productive: users can create and understand expressions they have never encountered before. Combining a limited inventory of units according to structural patterns enables an open-ended range of messages. Language also permits reference to absent objects, past events, imagined situations, and abstract relationships.
Many linguistic signs are conventional rather than naturally determined. Nothing in the sound of the English word “tree” requires it to denote that object. Nevertheless, iconicity also occurs: some expressions resemble aspects of their meanings, notably in sound symbolism and many signed forms.
Animal communication systems can convey complex information and may share individual features with language. No nonhuman communication system, however, has been shown to match the full combination of structural and expressive capacities found in human languages. The evolutionary origins of this combination remain uncertain because spoken and signed language leave little direct prehistoric evidence.
Acquisition and cognition
Language acquisition begins through exposure and interaction. Children learn patterns of sound or sign, vocabulary, and grammatical organization without needing explicit instruction in every rule. Development varies with the language, the individual, and the accessibility of linguistic input.
Language processing involves distributed networks in the brain, alongside systems supporting memory, perception, and attention. It cannot be reduced to a single isolated brain region. Researchers investigate how biological capacities and experience jointly support learning, and different theories assign them different explanatory roles.
Multilingualism is common worldwide. People may acquire several languages from early childhood or learn additional languages later. Their proficiency can differ across speaking, signing, understanding, reading, and writing, and across social settings. Language can influence attention and habitual categorization, but it does not rigidly determine everything a person can think.
Diversity and classification
There are thousands of living languages. Exact counts depend on documentation and on decisions about distinguishing languages from varieties. Languages are unevenly distributed geographically, and the number of users ranges from small communities to populations numbering hundreds of millions.
A language family groups languages descended from a common ancestor. For example, English belongs to the Germanic branch of the Indo-European family, while Latin is the ancestor of the Romance languages. Genealogical classification differs from typological classification, which compares structural features regardless of ancestry.
A dialect is a variety associated with a region or social group. All dialects have systematic grammar; the term does not inherently indicate an inferior or incomplete language. Mutual intelligibility is useful in classification but is not an absolute test. Historical identity, standardization, and community conventions also affect distinctions between languages and dialects.
Change and contact
Languages change in pronunciation, vocabulary, grammar, and meaning. Historical linguistics investigates these processes and uses recurring correspondences among related languages to reconstruct aspects of earlier forms.
Contact through migration, trade, and other interactions can produce borrowing and structural influence. Speakers may alternate between languages within a conversation, a practice called code-switching. Borrowing a word does not by itself make two languages genealogically related.
Translation transfers meaning between languages, but correspondence is rarely one-to-one. Differences in grammar, cultural knowledge, register, and implication require interpretation rather than simple word substitution.
Social use and transmission
Sociolinguistics examines relationships between linguistic variation and social life. Users adapt their language to audiences, situations, and purposes. Formal and informal registers, professional terminology, and regional forms can coexist within one community.
Standard languages are typically codified through dictionaries, grammatical descriptions, publishing, and education. Their institutional status does not imply greater inherent expressive capacity. Language also sustains literature and oral traditions, transmitting narratives and knowledge across generations.
Language endangerment occurs when intergenerational transmission weakens and communities increasingly use other languages. Documentation records linguistic knowledge, while revitalization efforts seek to expand opportunities for learning and use.
Writing and digital technology
Writing allows linguistic messages to persist beyond immediate interaction. Printing expanded textual circulation, and the internet supports communication across speech, text, video, and signing.
Natural language processing develops computational methods for analyzing and generating human language. Unlike natural languages, a programming language is designed to express instructions or computations under explicitly specified rules. Digital tools can support translation, transcription, and linguistic documentation, but their coverage and accuracy vary substantially across languages.