Fortis and 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).