Transphonologization
In historical linguistics, transphonologisation (also known as rephonologisation or cheshirisation, see below) is a type of sound change whereby a phonemic contrast that used to involve a certain feature X evolves in such a way that the contrast is preserved, yet becomes associated with a different feature Y. For example, a language contrasting two words */sat/ vs. */san/ may evolve historically so that final consonants are dropped, yet the modern language preserves the contrast through the nature of the vowel, as in a pair /sa/ vs.