betacism

In historical linguistics, betacism ( , ) is a sound change in which (the voiced bilabial plosive, as in bane) and (the voiced labiodental fricative , as in vane) are confused. The final result of the process can be either /b/ → [v] or /v/ → [b]. Betacism is a fairly common phenomenon; it has taken place in Greek, Hebrew, and several Romance languages.

==Greek== In Classical Greek, the letter beta ⟨β⟩ denoted . As a result of betacism, it has come to denote in Modern Greek, a process which probably began during the Koine Greek period, approximately in the 1st century CE, along with the spirantization of the sounds represented by the letters . Modern (and earlier Medieval) Greek uses the digraph ⟨μπ⟩ to represent . Indeed, this is the origin of the word betacism.