In phonetics and phonology, a sonorant or resonant is a speech sound that is produced with continuous, non-turbulent airflow in the vocal tract; these are the manners of articulation that are most often voiced in the world's languages. Vowels are sonorants, as are consonants like /m/ and /l/: approximants, nasals, flaps or taps, and most trills.
Contents
In older usage, only the term resonant was used with this meaning, and sonorant was a narrower term, referring to all resonants except vowels and semivowels.
Types
Whereas obstruents are frequently voiceless, sonorants are almost always voiced. A typical sonorant consonant inventory found in many languages comprises the following: two nasals /m/, /n/, two semivowels /w/, /j/, and two liquids /l/, /r/.
In the sonority hierarchy, all sounds higher than fricatives are sonorants. They can therefore form the nucleus of a syllable in languages that place that distinction at that level of sonority; see Syllable for details.
Sonorants contrast with obstruents, which do stop or cause turbulence in the airflow. The latter group includes fricatives and stops (for example, /s/ and /t/).
Among consonants pronounced in the back in the mouth or in the throat, the distinction between an approximant and a voiced fricative is so blurred that no language is known to contrast them. Thus, uvular, pharyngeal, and glottal fricatives never contrast with approximants.
Voiceless
Voiceless resonants are rare; they occur as phonemes in only about five percent of the world's languages. Voiceless sonorants tend to be extremely quiet and very difficult to recognise even for those people whose language does contain them.
In every case where a voiceless sonorant does occur, there is a contrasting voiced sonorant (i.e. whenever a language contains a phoneme such as /r̥/, it also contains a corresponding voiced phoneme, /r/ in this case)
Voiceless sonorants are most common around the Pacific Ocean — in Oceania, East Asia, and North and South America — in certain language families, such as Austronesian, Sino-Tibetan, Na-Dene and Eskimo–Aleut.
One European language with voiceless sonorants is Welsh, which contains a phonemic voiceless alveolar trill /r̥/ along with three voiceless nasals: velar, alveolar, and labial.
Voiceless [r̥ l̥ ʍ], and possibly [m̥ n̥], are hypothesized to have occurred in various dialects of Ancient Greek. The Attic dialect of the Classical period likely had [r̥] as the regular allophone of /r/ at the beginning of words, and possibly when doubled inside words. Hence, many English words from Ancient Greek roots have rh initially and rrh medially: rhetoric, diarrhea.
Examples
English has the following sonorant consonantal phonemes: /l/, /m/, /n/, /ŋ/, /ɹ/, /w/, /j/.
Old Irish had one of the most complex sonorant systems recorded in linguistics, with 12 coronal sonorants alone. Coronal laterals, nasals, and rhotics had a fortis–lenis and a palatalization contrast: /N, n, Nʲ, nʲ, R, r, Rʲ, rʲ, L, l, Lʲ, lʲ/. There were also /ŋ, ŋʲ, m/ and /mʲ/, making 16 sonorant phonemes in total.
Sound changes
Voiceless resonants have a strong tendency to either revoice or undergo fortition, for example to form a fricative like /ç/ or /ɬ/.