tugevadavad
Tugevadavad, commonly referred to as strong verbs, are a class of Estonian verbs distinguished from weak verbs by the way their past tense is formed. Rather than adding a uniform suffix to the stem, strong verbs typically change the stem vowel or consonant in the past tense, a phenomenon known as ablaut or stem alternation. This makes their across-form patterns more varied and, in some cases, less predictable.
In practice, strong verbs often show changes in the core of the verb when moving from present
Historically, the distinction between strong and weak verbs reflects developments in Proto-Finnic and the later Estonian
Overall, the category highlights a key area of Estonian morphology where internal stem changes carry the past