Betacism

Betacism is a fairly common phenomenon; it has taken place in Greek, Hebrew, Japanese, and several Romance languages.

A famous medieval Latin saying states: Beati hispani, quibus vivere bibere est.

Translation: Fortunate are the Hispani, for whom living is drinking.The saying is a pun referring to the fact that the Iberians would generally pronounce the letter v the same as b (which uses the sound [b] or [β]) instead of [w] or [v].

In Latin, the words vīvĕre ("to live") and bĭbĕre ("to drink") are distinguished by the use of the letters v and b, thus creating a point of confusion in the Iberian pronunciation.

Betacism occurred in Ancient Hebrew; the sound [b] (denoted ⟨ב⟩) changed to [β] and eventually to [v] except when geminated or when following a consonant or pause.