According to Merritt Ruhlen, over 50% of occurrences of phonemic labialization are applied to dorsal (velar and uvular) consonants, while coronals are usually left out. There are a few families where this doesn't apply because labialization results from historically rounded vowels, such as the Northwest Caucasian languages, but it appears to exist most of the time. Why is this?

  • 1
    Interestingly, rounded vowels are also usually "velar and uvular" [u o ɔ] other rounded vowels are uncommon cross-linguistically, as far as I know. Dec 21, 2018 at 20:36
  • 1
    It seems that rounding and backness often occur together. Dec 21, 2018 at 20:40
  • @tobiornottobi, aren't true back vowels further back than typical velars? If I recall correctly, the 'semivowel' form of /ɑ/ is pharyngeal, which would imply the same place of articulation for the vowel.
    – snorepion
    Dec 22, 2018 at 15:38
  • 1
    /ɑ/ already seems to be more common than the rounded equivalent, if we take the cardinal vowels into consideration. It seems more consequent to me to compare typical velars and typical back vowels or "true" velars and "true" back vowels. Depending on the language either the velar consonant or the back vowel may be advanced. I can say that your statement applies to my native German accent, though: velar plosives are more advanced than the back vowels, I think, (it doesn't seem to apply to the fricative [x]). Dec 22, 2018 at 19:58

2 Answers 2


The explanation is based on phonetics. A back (velar or uvular) constriction causes the second formant to be low, as does rounding. Together, labiovelars have a very low F2, and that results in a very distinctive sound. A coronal consonant on the other hand has a high F2, but adding rounding lowers F2, so the resulting sound is perceptually less distinctive. Ohala & Lorenz "the story of w" explains the acoustic basis for labiovelar preferences (though not including [tʷ] compared to [t])

  • 1
    That's really interesting. Is that also related to why you tend to see /w/ rather than /ɰ/?
    – snorepion
    Dec 22, 2018 at 3:02
  • 2
    I have to think about that. The thing is, [ɰ] is the glide version of [k], as [w] is the glide version of [kʷ]. But [k] is much more frequent compared to [kʷ], so ... as I say, I must mull this over.
    – user6726
    Dec 22, 2018 at 3:12
  • 1
    Having thought it over, I'm in over my head. Keith Johnson probably knows, and may tell. My conjecture is that a narrowing of the vocal tract for an approximant versus a complete constriction for a stop have different effects on resonance .
    – user6726
    Dec 30, 2018 at 2:35

Labialisation has nothing to do with a low F2. If it was the case laryngeal and pharyngealised consonants, which have also a low F2, will know in the same manner a high frequency of labialisation. But such observations have not been noticed, the perception is not at stake here. So we have to explain that in another way.

According to me, the answer is probably a articulatory problem. The sequences [ku] / [kw] or [gu] / [gw] cannot stand together, because they are homorganic (same place of articulation: dorsal). In consequence, a coalescence or a assimilation phenomenon will occur more easily, facilitating the labialisation of these consonants.

Another point, as the rounding posterior vowels and velar consonants are more frequently found among the world languages, so, automatically, labialised velar will be statistically more representative in comparison to others.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.