Konsonanttigradation

Konsonanttigradation, or consonant gradation, is a phonological phenomenon found in some Finnic languages where the consonant in a stem alternates between a strong (full) grade and a weak (reduced) grade in different inflectional forms. The strong grade typically appears in the dictionary or base form, while the weak grade surfaces in inflected forms or after certain suffixes. The exact alternations depend on the language, the word, and the dialect.

In practice, gradation often affects stops and nasals in consonant clusters. Common patterns include the reduction or loss of a doubled or geminated consonant (for example, a strong kk, tt, or pp becoming a single k, t, or p in some forms) or changes in voicing. The changes are triggered by grammatical context, such as case, number, or certain affixes, and can also be influenced by phonological environment within the word. Examples from Finnish illustrate the idea: kukka (flower) has the strong grade kk, while the genitive singular form kukan shows a weak grade with the kk reduced to k; pappi (priest) becomes papin in the genitive, showing pp becoming p.

The feature is most developed in Finnish and is also present in related Finnic languages to varying degrees. It is a long-standing historical process, traced to consonant mutation and lenition patterns in Proto-Finnic, and it remains an important part of modern Finnish morphology. While some words show clear gradation, others are irregular, and the exact patterns can vary by word class and dialect.