Reconstruction:Proto-Finnic/-t'ak

Etymology 1
Originally a variant of when attached to vowel stems and landing on an odd syllable, while  would have been on even syllables or when attached to consonant stems.

Etymology 2
A later development from etymology 1 by analogy with causative derivatives using, thus analogously making the shorter suffix anticausative.

Reconstruction notes
Hakulinen (1979) distinguishes between stems and  stems (the latter of which would include  and ), after Rapola (1922). However, YSuS reconstructs both verbs with, so reconstructing this distinction already in Proto-Finnic appears to be considered obsolete (if it ever existed, it would instead be later secondary development).

Derived terms

 * *kadot'ak (&larr; *katodak)
 * *kadot'ak (&larr; *katodak)
 * *kadot'ak (&larr; *katodak)
 * *kadot'ak (&larr; *katodak)

Etymology 3
From.

The change >  is likely by analogy with the passive and participle stems, as well as the causative, where the added  incurred a regular  >. This change was then generalized to other forms.

The consonant stem, i.e. the stem when followed by a (such as in the passive and infinitive forms) or  (in the imperative forms), has been reformed to , due to confusion with verbs using the suffix  ( added to -n- stems). The first infinitive form would have, with this ending, become >  >  (with simplification of the then phonotactically impossible cluster : compare  < ).

Like and the comparative ending  (which see for more), this verb consistently induces a stem vowel change  >.

Etymology 4
From. Cognate with 🇨🇬 (in e.g. 🇨🇬).

Usage notes
This suffix >  is often reduced to simply -i- in descendants. This is regular (compare, for instance, the genitive plural ending becoming  in Finnish, like in  >, now dialectal).

Inflection
Secondary stem variant.

Etymology 5
From, possibly a variant of , whence.