Fortis and lenis

In linguistics, fortis and lenis (ˈfɔːrtᵻs and ˈliːnᵻs,_ˈlɛnᵻs; Latin for "strong" and "weak"), sometimes identified with 'tense' and 'lax', are pronunciations of consonants with relatively greater and lesser energy, respectively. 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, 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, under-researched or unimportant. Later studies have shown that articulatory strength is not completely irrelevant. The articulators in the mouth can move with a greater velocity and/or with higher electromyographic activation levels of the relevant articulatory muscles with fortis consonants than with lenis ones. Generally, voiceless stops have greater oral pressure than voiced ones, which could explain this greater articulatory energy. In Ewe, for example, the lips reach closure faster in articulating /p/ than in /b/, making the lip closure longer.