|Sound change and alternation|
- "Lip rounding" redirects here. See Roundedness for the lip rounding of vowels.
Labialization is a secondary articulatory feature of sounds in some languages. Labialized sounds involve the lips while the remainder of the oral cavity produces another sound. The term is normally restricted to consonants. When vowels involve the lips, they are called rounded.
Labialization may also refer to a type of assimilation process.
Labialization is the most widespread secondary articulation in the world's languages. It is phonemically contrastive in Northwest Caucasian (e.g. Adyghe), Athabaskan, and Salishan language families, among others. This contrast is reconstructed also for Proto-Indo-European, the common ancestor of the Indo-European languages.
American English has three degrees of labialization: tight rounded (/w/), slight rounded (/ʃ/, /ʒ/, /tʃ/, /dʒ/, initial /r/), and unrounded, which in vowels is sometimes called 'spread'. These secondary articulations are not universal. For example, French shares the English slight rounding of /ʃ/, /ʒ/ while Russian does not have slight rounding in its postalveolar fricatives (/ʂ ʐ ɕ ʑ/).
Types of labialization
Out of 706 language inventories surveyed by Ruhlen (1976), labialization occurred most often with velar (42%) and uvular (15%) segments and least often with dental and alveolar segments. With non-dorsal consonants, labialization may include velarization as well. Labialization is not restricted to lip-rounding. The following articulations have either been described as labialization, or been found as allophonic realizations of prototypical labialization:
- Labial rounding, with or without protrusion of the lips (found in Navajo)
- Labiodental frication, found in Abkhaz
- Bilabial frication, found in Ubykh
- Bilabial trill, found in Ubykh
- Bilabial plosion, found in Ubykh
- "Labialization" (/w/, /ɡʷ/, and /kʷ/) without noticeable rounding (protrusion) of the lips, found in the Iroquoian languages. It may be that they are compressed.
- Rounding without velarization, found in Shona and in the Bzyb dialect of Abkhaz.
Eastern Arrernte has labialization at all places and manners of articulation; this derives historically from adjacent rounded vowels, as is also the case of the Northwest Caucasian languages. Marshallese also has labialization at all places of articulation except for coronal obstruents.
In the International Phonetic Alphabet, labialization of velar consonants is indicated with a raised w modifier [ʷ] (Unicode U+02B7), as in /kʷ/. (Elsewhere this diacritic generally indicates simultaneous labialization and velarization.) There are also diacritics, respectively [ɔ̹], [ɔ̜], to indicate greater or lesser degrees of rounding. These are normally used with vowels, but may occur with consonants. For example, in the Athabaskan language Hupa, voiceless velar fricatives distinguish three degrees of labialization, transcribed either /x/, /x̹/, /xʷ/ or /x/, /x̜ʷ/, /xʷ/.
If precision is desired, the Abkhaz and Ubykh articulations may be transcribed with the appropriate fricative or trill raised as a diacritic: [tᵛ], [tᵝ], [tʙ], [tᵖ].
For simple labialization, Ladefoged & Maddieson (1996) resurrected an old IPA symbol, [ ̫]. However, their chief example is Shona sv and zv, which they transcribe /s̫/ and /z̫/ but which actually seem to be whistled sibilants, without necessarily being labialized. The open rounding of English /ʃ/ is also unvelarized.
Labialization also refers to a specific type of assimilatory process where a given sound become labialized due to the influence of neighboring labial sounds. For example, /k/ may become /kʷ/ in the environment of /o/, or /a/ may become /o/ in the environment of /p/ or /kʷ/.
In the Northwest Caucasian languages as well as some Australian languages rounding has shifted from the vowels to the consonants, producing a wide range of labialized consonants and leaving in some cases only two phonemic vowels. This appears to have been the case in Ubykh and Eastern Arrernte, for example. The labial vowel sounds usually still remain, but only as allophones next to the now-labial consonant sounds.
- labialized voiceless alveolar plosive [tʷ] (Listen) (in Archi, Abkhaz, Lao, Paha)
- labialized voiced alveolar plosive [dʷ] (Listen) (in Archi, Abkhaz)
- labialized voiceless palatal plosive [cʷ] (in Lao)
- labialized voiceless velar plosive [kʷ] (Listen) (in Northwest Caucasian languages, Nahuatl, Taos, Chipewyan, Hadza, Gwich’in, Tlingit, Akan, Nez Perce, Archi, Cantonese, Wari’, Chaha, Dahalo, Hausa, Igbo, Italian, Lao, Nahuatl, Paha, Thai, Tigrinya)
- labialized voiced velar plosive [gʷ] (Listen) (in Northwest Caucasian languages, Akan, Archi, Chaha, Dahalo, Hausa, Oowekyala, Hadza, Igbo, Gwich’in, Paha, Tigrinya)
- labialized voiceless uvular plosive [qʷ] (Listen) (in Northwest Caucasian languages, Paha, Tlingit, Nez Perce)
- labialized voiced uvular plosive [ɢʷ] (Listen) (in Oowekyala, Kwak'wala, Tsakhur)
- labialized glottal stop [ʔʷ] (Listen) (in Circassian, Lao, Tlingit)
- labialized voiceless bilabial plosive [pʷ] (Listen) (in Chaha, Paha)
- labialized voiced bilabial plosive [bʷ] (Listen) (in Chaha, Paha)
- labialized prenasalized voiced bilabial plosive [ᵐbʷ] (in Tamambo)
- labialized voiceless labiovelar plosive [k͡pʷ] (in Mwotlap)
- labialized prenasalized voiced labial-velar plosive [ᵑg͡bʷ] (in Volow)
- labialized voiceless alveolar affricate [tsʷ] (Listen) (in Circassian, Archi, Lezgian, Tsakhur)
- labialized voiced alveolar affricate [dzʷ] (Listen) (in Circassian, Dahalo)
- labialized voiceless palato-alveolar affricate [tʃʷ] (Listen) (in Circassian, Archi, Abaza, Paha, Aghul)
- labialized voiced palato-alveolar affricate [dʒʷ] (Listen) (in Circassian, Abaza, Aghul, Tsakhur)
- labialized voiceless alveolo-palatal affricate [tɕʷ] (in Abkhaz, Akan)
- labialized voiced alveolo-palatal affricate [dʑʷ] (in Abkhaz, Akan)
- labialized voiceless velar affricate [kxʷ] (Listen) (in Navajo)
- labialized voiceless uvular affricate [qχʷ] (Listen) (in Circassian, Lillooet)
- labialized voiceless alveolar sibilant [sʷ] (Listen) (in Archi, Lao, Lezgian)
- labialized voiced alveolar sibilant [zʷ] (Listen) (in Archi, Tsakhur, Lezgian)
- labialized voiceless palato-alveolar sibilant [ʃʷ] (Listen) (in Archi, Abaza, Abkhaz, Paha, Aghul)
- labialized voiced palato-alveolar sibilant [ʒʷ] (Listen) (in Archi, Abaza, Abkhaz, Aghul)
- labialized voiceless retroflex sibilant [ʂʷ] (Listen) (in Circassian)
- labialized voiced retroflex sibilant [ʐʷ] (Listen) (in Circassian)
- labialized voiceless alveolo-palatal sibilant [ɕʷ] (Listen) (in Abkhaz)
- labialized voiced alveolo-palatal sibilant [ʑʷ] (Listen) (in Abkhaz)
Central non-sibilant fricatives
- labialized voiceless bilabial fricative [ɸʷ]
- labialized voiced bilabial fricative [βʷ] (in Tamambo)
- labialized voiceless labiodental fricative [fʷ] (Listen) (in Hadza, Chaha)
- labialized voiced labiodental fricative [vʷ] (Listen)
- labialized voiceless dental fricative [θʷ] (Listen) (in Paha)
- labialized voiced dental fricative [ðʷ] (Listen) (in Paha)
- labialized voiceless palatal fricative [çʷ] (in Akan)
- labialized voiceless velar fricative [xʷ] (Listen) (in Circassian, Abaza, Avestan, Chaha, Oowekyala, Taos, Navajo, Tigrinya, Lillooet, Tlingit)
- labialized voiced velar fricative [ɣʷ] (Listen) (in Abaza, Navajo, Lillooet, Gwich’in)
- labialized voiceless uvular fricative [χʷ] (Listen) (in Circassian, Abkhaz, Archi, Lillooet, Tlingit, Wari’, Chipewyan, Oowekyala)
- labialized voiced uvular fricative [ʁʷ] (Listen) (in Circassian, Abkhaz, Chipewyan)
- labialized voiceless pharyngeal fricative [ħʷ] (Listen) (in Abaza, Abkhaz)
- labialized voiced pharyngeal fricative [ʕʷ] (Listen) (in Abaza, Lillooet)
- labialized voiceless alveolar lateral fricative [ɬʷ] (Listen) (in Dahalo)
- labialized voiceless velar lateral fricative [ʟ̝̊ʷ] (Listen) (in Archi)
- labialized bilabial nasal [mʷ] (Listen) (in Chaha, Paha, Tamambo)
- labialized palatal nasal [ɲʷ] (in Akan)
- labialized velar nasal [ŋʷ] (in Akan, Avestan, Lao)
- labialized labial-velar nasal [ŋ͡mʷ] (in Mwotlap)
- labialized alveolar lateral approximant [lʷ] (Listen) (in Lao)
- labialized palatal approximant [ɥ] [jʷ] (Listen) (in Abkhaz, Akan, French, Mandarin, Paha)
- labialized velar approximant (voiced) [w] (widespread; in every above-mentioned language, as well as e.g. Arabic, English, Korean, Vietnamese)
- voiceless labialized velar approximant [ʍ] (in certain dialects of English)
- nasal labialized velar approximant [w̃]