In linguistics, a tenuis consonant // is an obstruent that is unvoiced, unaspirated, unpalatalized, and unglottalized. That is, it has the "plain" phonation of [p, t, ts, tʃ, k] with a voice onset time close to zero (a zero-VOT consonant), as Spanish p, t, ch, k or as English p, t, k after s (spy, sty, sky).
For most languages, the distinction is relevant only for stops and affricates. However, a few languages have analogous series in the fricatives; Mazahua, for example, has the ejective, aspirated, and voiced fricatives /sʼ sʰ z/ alongside tenuis /s/, parallel to the stops /ɗ tʼ tʰ d/ alongside tenuis /t/. Many click languages have tenuis click consonants alongside voiced, aspirated and glottalized series.
In transcription, tenuis consonants are not normally marked explicitly, and consonants written with voiceless IPA letters such as ⟨p, t, ts, tʃ, k⟩ are typically assumed to be unaspirated and unglottalized unless indicated otherwise. However, aspiration is often left untranscribed when no contrast needs to be made (for example, in English), and to address this there is an explicit diacritic for a lack of aspiration in the Extensions to the IPA, a superscript equal sign: ⟨p˭, t˭, ts˭, tʃ˭, k˭⟩. This is sometimes seen in phonetic descriptions of languages. There are also languages, such as the Northern Ryukyuan languages, where the phonologically unmarked sound is aspirated, and the tenuis consonants are marked and transcribed explicitly.
In Unicode, the symbol is encoded at U+02ED ˭ MODIFIER LETTER UNASPIRATED (HTML
An early IPA convention was to write the tenuis stops ⟨pᵇ, tᵈ, kᶢ⟩ etc. when the plain letters ⟨p, t, k⟩ were used for aspirated consonants (as they are in English). Thus [ˈpaɪ] 'pie' vs. [ˈspᵇaɪ] 'spy'.
The term tenuis comes from Latin translations of Ancient Greek grammar, which differentiated three series of consonants, voiced β δ γ /b d ɡ/, aspirate φ θ χ /pʰ tʰ kʰ/, and tenuis π τ κ /p˭ t˭ k˭/. The three series have analogs in many other languages. The term was widely used in 19th-century philology but became uncommon in the 20th.
However, common replacement words such as "plain", "unvoiced", and "unaspirated" are ambiguous: besides the tenuis alveolar stop [t˭], the aspirated and ejective stops [tʰ] and [tʼ] are unvoiced, the voiced and ejective stops [d] and [tʼ] are unaspirated, and, in the proper context, all four are called "plain", as is the alveolar nasal stop [n].
- Bussmann, 1996. Routledge Dictionary of Language and Linguistics
- R.L. Trask, 1996. A Dictionary of Phonetics and Phonology.