(phonetics, phonology) A weakening of articulation causing a consonant to become lenis (soft).
2008, Krzysztof Jaskula, Celtic, Joaquim Brandão de Carvalho, Tobias Scheer, Philippe Ségéral (editors), Lenition and Fortition, Studies in Generative Grammar: 99, page 347,
As for Goidelic languages, the situation is clearer because Lenition III in this subfamily consisted in losing the same property as the first two lenitions, namely stopness.
2011, Naomi Gurevich, 66: Lenition, Marc van Oostendorp, Colin J. Ewen, Elizabeth V. Hume, Keren Rice (editors), The Blackwell Companion to Phonology, Volume III: Phonological Processes, page 1573,
Five general patterns of lenitions – all based to some extent on empirical data – are identified.
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