Plain-language explanation.
Language typology classifies the world's languages according to their structural features — how they build words, how they order sentences, and how they mark grammatical relationships. By comparing languages systematically, typologists discover language universals — features found in all or most languages — and language families with common structural patterns.
Core concepts and standard treatment.
Language typology operates across levels: morphological typology (isolating — Mandarin, one morpheme per word; agglutinative — Turkish, transparent stacking of morphemes; fusional — Latin, morphemes fused together; polysynthetic — Inuktitut, entire clauses expressed in one word), syntactic typology (word order: SOV — Japanese, Turkish; SVO — English, Mandarin; VSO — Arabic, Welsh), and semantic typology (colour, spatial, and kinship terminologies).
Deeper theory, debates and edge cases.
Language universals and implicational universals (Greenberg's universals): if a language has feature X, it also has feature Y (e.g., if a language has object-final order, it tends to have postpositions rather than prepositions). Functional typology argues implicational universals reflect cognitive, communicative, and processing motivations rather than innate UG constraints. Ergativity — where the subject of an intransitive verb is marked like the object of a transitive verb, rather than like its subject — is a crosslinguistically common pattern absent from English that challenges purely English-based grammatical theory.
How it is applied in practice.
World Atlas of Language Structures (WALS) provides the primary cross-linguistic database: 192 features coded for 2,662 languages. Typological distributions inform diachronic language change: Dryer's word order correlations show that head-final languages tend to have dependent-final order throughout the noun phrase and clause. Linguistic typology has implications for NLP: multilingual models that must handle typologically diverse languages (SOV vs. SVO, free vs. fixed word order, morphologically rich vs. isolating) require architecture choices that accommodate this variation.