Sonorant

Voiceless

Voiceless sonorants are rare; they occur as phonemes in only about 5% of the world's languages.^[3] They tend to be extremely quiet and difficult to recognise, even for those people whose language has them.

In every case of a voiceless sonorant occurring, there is a contrasting voiced sonorant. In other words, whenever a language contains a phoneme such as /ʍ/, it also contains a corresponding voiced phoneme such as /w/.^{[citation needed]}

Voiceless sonorants are most common around the Pacific Ocean (in Oceania, East Asia, and North and South America) and in certain language families (such as Austronesian, Sino-Tibetan, Na-Dene and Eskimo–Aleut).

One European language with voiceless sonorants is Welsh. Its phonology contains a phonemic voiceless alveolar trill /r̥/, along with three voiceless nasals: bilabial, alveolar, and velar /m̥ n̥ ŋ̊/.

Another European language with voiceless sonorants is Icelandic, with [l̥ r̥ m̥ n̥ ɲ̊ ŋ̊ ȷ̊] for the corresponding voiced sonorants [l r m n ɲ ŋ j].

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 it was doubled inside words. Hence, many English words from Ancient Greek roots have rh initially and rrh medially: rhetoric, diarrhea.

Voiceless vowels are allophonic in many languages, particularly when surrounding voiceless consonants, but their phonological status as contrastive phonemes lacks strong evidence;^[4] cases where they were previously reported to have contrastive status have failed corroboration in later studies.

Glottalic

Most sonorants have glottalized variants. In languages that use Latin scripts, they are often written with a modifier apostrophe, either preceding ⟨ʼw⟩, succeeding ⟨wʼ⟩, or above ⟨w̓⟩. Numerous studies have shown that the timing of glottalization for sonorants is fluid, and that they may be realized with:

• preglottalization (glottal onset), such as [ˀw];
• postglottalization (glottal offset), such as [wˀ];
• laryngealization (creaky voice) for the duration of the sounds, such as [w̰];
• or a combination of the aforementioned possibilities.^[5][6][7][8]

For simplicity, the remainder of this section will transcribe these sounds with a preceding superscript glottal stop, as in ⟨ˀw⟩, but these transcriptions should not be assumed to be phonetically precise in describing the type of glottalization; they are merely representative.

It has been noted that glottal stops with palatalization and labialization, respectively /ʔʲ/ and /ʔʷ/, are quite similar to the glottalized sonorants /ˀj/ and /ˀw/, and either case may be analyzed instead as sequences, /ʔj/ and /ʔw/; the specific interpretation of these sounds is mostly dependent upon how they pattern with other sounds within a particular language's phonological structure.^[9] Some languages (such as Lillooet) may still contrast glottalized sonorants with glottal–sonorant or sonorant–glottal sequences.

Glottalized vowels occur in a variety of languages and are perhaps the most common examples of glottalized sonorants. For consonants, the most common examples cross-linguistically of glottalized sonorants are the aforementioned palatal and labiovelar semivowels /ˀj/ and /ˀw/, the alveolar lateral /ˀl/, and the bilabial and alveolar nasals /ˀm/ and /ˀn/. Among others, they are particularly common in the Salish, Tsimshianic, and Wakashan language families of the Pacific Northwest, as well as several languages of the Atlantic–Congo family of Sub-Saharan Africa and the Kra–Dai family of mainland Southeast Asia and southern China.

Of the rarer glottalized sonorant consonants:

• Jingpo, Khmu, Kuyubí, and Mangbai have a palatal nasal /ˀɲ/
• Chemehuevi, Deg Xinag, Hagei, Jingpo, Lummi, Khmu, Wui, and Yapese have a velar nasal /ˀŋ/
• Lekwungen, Klallam, Saanich and Samish have a post-velar or uvular nasal /ˀɴ/
• Lillooet, Shuswap, and Coast Tsimshian have a non-labial velar approximant /ˀɰ ~ ˀɣ᫛/
• Coeur d'Alene, Lillooet, Okanagan, Shuswap, Spokane, and Thompson have both plain and labialized pharyngeal approximants /ˀʕ̞, ˀʕ̞ʷ/
• Spokane and Yurok have an alveolar approximant /ˀɹ/
• Jingpo has a retroflex approximant /ˀɻ/