Taivutusisä

Taivutusisä is a term used in Finnish grammar to refer to the inflectional stem of a word—the part of the word to which inflectional endings are attached to form different grammatical forms such as cases and numbers. The taivutusisä serves as the base for taivutus (inflection). In practice, the taivutusisä is the form you obtain when you strip away the inflectional endings from a given inflected form.

The concept helps distinguish between the dictionary form (perusmuoto) and the actual inflected forms, especially in cases where the stem remains stable across forms or where phonological or derivational processes cause subtle stem alternations. For many common nouns and adjectives, the taivutusisä coincides with the part of the word that appears in the dictionary form, making the inflectional endings the only visible change.

Identifying the taivutusisä involves removing known inflectional endings from a form and inspecting the remaining base. This approach is useful in linguistic analysis, language teaching, and language technology, where parsers and dictionaries rely on consistent stems to generate or analyze inflected forms.

Examples help illustrate the idea. For the noun talo (house), a typical taivutusisä is talo-; forms such as talon (genitive) or talossa (inessive) come from attaching endings to that stem. For the noun kissa (cat), the taivutusisä is kissa-; inflected forms like kissan (genitive) or kissaa (partitive) are built from that stem plus the respective endings. In some cases, languages exhibit stem changes, where the taivutusisä may differ between forms, reflecting phonological or derivational adjustments.

See also: perusmuoto, taivutus, stem, Finnish grammar.