iotation

noun2

1. •
   A specific occurrence of palatalization that occurred in the Proto-Slavic language, in which a consonant combined with the palatal approximant /j/ to form a palatalized consonant.
2. •
   Any similar process occurring in a later Slavic language or elsewhere.

   • A form of iotation in the Serbo-Croatian language: s (/s/) + j (/ʲ/) = sj (/sʲ/), which is then superseded into ś (/ɕ/)