Lenis

In linguistics, fortis and lenis (/ˈfɔːrtɪs ˈliːnɪs/; Latin for "strong" and "weak"), sometimes identified with tense and lax, are pronunciations of consonants with relatively greater and lesser energy. English has fortis consonants, such as the p in pat, with a corresponding lenis consonant, such as the b in bat. Fortis and lenis consonants may be distinguished by tenseness or other characteristics, such as voicing, aspiration, glottalization, velarization, length, and length of nearby vowels. Fortis and lenis were coined for languages where the contrast between sounds such as p and b does not involve voicing (vibration of the vocal cords).

Originally, the terms were used to refer to an impressionistic sense of strength differences, though more sophisticated instruments eventually gave the opportunity to search for the acoustic and articulatory signs. For example, Malécot (1968) tested whether articulatory strength could be detected by measuring the force of the contact between the articulators or of the peak pressure in the mouth. Because such studies initially found little to substantiate the terminology, phoneticians have largely ceased using them, though they are still commonly used as "phonological labels for specifying a dichotomy when used language-specifically." This can be useful when the actual articulatory features underlying the distinction are unknown or unimportant.

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