Lenition is a kind of consonant mutation that appears in many languages. Along with assimilation, it's one of the primary sources of historical change of languages. Lenition means 'softening' or 'weakening' (from Latin lenis = weak), and it refers to the change of a consonant considered 'stronger' into one considered 'weaker' (or fortis → lenis). Common examples include voicing or sonorization, as in [f] → [v]; affrication or spirantization (turning into an affricate or a fricati… (More on Lenition)