perustasanan

Perustasanan is a Finnish linguistic term referring to the base form of a word, commonly equated with the lemma or dictionary form. It denotes the canonical form of a word that dictionaries and language-processing tools use as a reference point for all inflected variants.

The concept is related to, but distinct from, the idea of a root or stem. The root (juuri) is the smallest meaningful unit, whereas the perustasana is the reference form used for citation and linguistic analysis. For many parts of speech the perustasana corresponds to standard dictionary forms: nouns typically have the nominative singular as their perustasana, verbs the infinitive, and adjectives the positive form. This base form is the one that is typically listed in dictionaries and used in lemmatization.

Examples help illustrate the idea. The perustasana of talo (house) is talo; inflected forms include talon, talossa, taloja. The perustasana of puhua (to speak) is puhua; inflected forms include puhun, puhuu, puhui. The adjective kaunis (beautiful) has the perustasana kaunis, with inflected forms such as kauniin and kaunista. In verb conjugation, the infinitive serves as a stable reference point, while in nouns and adjectives the nominative or positive forms often function as the base.

Relevance and use: In dictionaries, language teaching, corpora, and natural language processing, the perustasana serves as the headword for lexemes. It is a fundamental concept for lemmatization, search indexing, and linguistic analysis. The term is often treated as synonymous with lemma or dictionary form, though terminology can vary across traditions.