Consonant Gradation

Consonant gradation is a type of consonant mutation, in which consonants alternate between various "grades". It is found in some Uralic languages such as Finnish, Estonian, Northern Sámi, and the Samoyed language Nganasan. In addition, it has been reconstructed for Proto-Germanic, the parent language of the Germanic languages. Of the Finnic languages, Votic is known for its extensive set of gradation patterns. Consonant gradation in some of these languages is not (or is no longer) purely phonological, although this may be surmised for various reconstructions of Proto-Finnic. In archiphonemic terms, the mutation is a type of lenition in which there are quantitative (e.g. /kː/ vs. /k/) as well as qualitative (e.g. /k/ vs. /v/) alternations.

What types of consonants and consonant clusters may undergo gradation vary from language to language; for example, Northern Sámi has three different grades (as well as having three quantities of consonant length), and also allows for quantitative gradation of its sonorants /l m n r/. Most Finnic languages, however, have two grades and only allow stops to undergo gradation. Languages may also have other constraints for loanwords; for example, loan words and some personal names in Finnish may have quantitative gradation, but not qualitative, thus auto does not become *audon '(the) car's', but remains auton.