keerdumine
Keerdumine is a term primarily used in Estonian linguistics to describe a specific type of consonant change that occurs within words. It refers to the phenomenon where a consonant's voicing status changes, specifically from voiceless to voiced or from voiced to voiceless, under certain phonological conditions. This change is often influenced by the surrounding sounds, particularly vowels and other consonants, and can be a regular, predictable process in Estonian grammar.
The most common manifestation of keerdumine involves the alternation between voiceless and voiced stops. For instance,