Muotoisuus

Muotoisuus is a linguistic term used to describe the extent to which a language or a lexical item exhibits morphologically conditioned variation in form. The word is formed from muoto meaning form and the suffix -isuus, which marks an abstract quality. In linguistic usage, muotoisuus often refers to the density and complexity of inflectional morphology: how many distinct word forms a lemma can take and how many grammatical categories are encoded through affixes, endings, or stem changes.

A language with high muotoisuus has a large set of inflected forms for its words and a rich system of paradigms; a language with low muotoisuus relies more on syntax or word order to convey grammatical meaning. The concept is used in language typology, language description, and computational linguistics to compare how languages encode information such as case, number, person, tense, mood, and aspect. It also informs discussions about language learning, processing, and acquisition.

Examples are often drawn from morphology-heavy languages. In Finnish, for instance, nouns participate in a system of multiple cases, and verbs inflect for person, number, tense, mood, and voice, while adjectives agree with nouns in number and case. Such patterns illustrate high muotoisuus in the sense of a dense and productive morphological system, contrasted with more isolating languages where form changes are limited.

See also: morphology, inflection, morphosyntax, language typology, Finnish language.