assibilation

Century Dictionary and Cyclopedia

1. n. The act of making sibilant; specifically, in philology, the change of a dental or guttural (or a labial) mute into a sibilant (s, z, sh, zh, ch = tsh, j = dzh), or into a sound approaching that of a sibilant, as for instance a palatal. This change usually results from a tendency to accommodate the mute to an immediately succeeding e, i, or y sound. Thus, t in the Latin natio becomes z (=ts) in the Italian nazione, and is pronounced s in the French nation and sh in the English nation. Similarly, the English t approaches or assumes the sound of ch before the y-sound contained in long u in nature, virtue, etc.

Wiktionary

1. n. linguistics A sound change resulting in a sibilant consonant, commonly the final phase of palatalization.

GNU Webster's 1913

1. n. Change of a non-sibilant letter to a sibilant, as of -tion to -shun, duke to ditch.

WordNet 3.0

1. n. pronunciation with a sibilant (hissing or whistling) sound
2. n. the development of a consonant phoneme into a sibilant