Of labials and labiodentals

[alice]

Are there any theories of phon[ology,etics] which explain why, in many (most?) languages, /p/ and /b/ are bilabials, but /f/ and /v/ are labiodentals?

I suppose

KEEP CALM and CONLANG ON; that's just what the LORD intended

will have to do in the absence of anything else, but if you feel compelled to answer

You haven't had your this morning, have you? /φ/ and/β/ are what you're looking for

you haven't understood the question.

[Frislander]

I think it's a matter of the relative strength of articulation and the loudness of the different consonants. In particular the bilabial fricatives are really weak in comparison to the labiodentals, which I reckon might be something to do with the fact that the passive articulator (the upper lip) is soft and fleshy compared to the hard teeth, so the fricatives might be made labiodental in order to make them easier to perceive in many cases. Also when the bilabial articulators aren't completely brought together the lower lip is close enough to the teeth that I reckon in a lot of cases it would turn them into labiodental fricatives almost automatically.

[mèþru]

Then why don't bilabial stops frequently shift to labiodentals?

[Frislander]

Because it is a lot easier to get complete closure between two lips than it is between the lower lip and the teeth. In fact before the advent of modern dentistry I reckon true labiodental stops would have been impossible for many people because of gaps between the teeth allowing airflow, when in order to even produce a stop by definition you need a complete closure blocking off the airflow.

[alice]

Because it is a lot easier to get complete closure between two lips than it is between the lower lip and the teeth. In fact before the advent of modern dentistry I reckon true labiodental stops would have been impossible for many people because of gaps between the teeth allowing airflow, when in order to even produce a stop by definition you need a complete closure blocking off the airflow.

Aha! I sense a paper: The impact of dentistry on contemporary phonetics. Except that "impact" means something else in dentistry, ouch.

[Pabappa]

But the difference is still salient for the fricatives. e.g. https://en.wikipedia.org/wiki/Ewe_language#Consonants has /f v/ vs /φ β/. There's also https://en.wikipedia.org/wiki/Shubi_language , distantly related, which by some analyses contrasts /p b/ vs the labiodental stops. However, some speakers use affricates instead of albiodentals. Which may be another reason: in languages that evolve true labiodental stops, they shift to affricates /pf bv/. Nasals cannot do this, which may explain the lack of labiodental nasals. though here again there is one example, https://en.wikipedia.org/wiki/Kukuya_language , which cannot be explained as just being /mv/ shoehorned in with the nasals because it also has a separate /mv/.
÷÷÷÷÷÷÷÷÷÷÷÷
ive used labiodentals in conlangs ... in 1994 i didnt know b etter so they were just present from the beginning. later, i explained they were present due to sound changes involving the sonority hierarchy, and were in free variation with sequences /pf bv mv/ because this language did not otherwise allow those sequences except over sllalbe boundaries.

[Frislander]

But the difference is still salient for the fricatives. e.g. https://en.wikipedia.org/wiki/Ewe_language#Consonants has /f v/ vs /φ β/.

I'm not saying bilabial fricatives are impossible - far from it! Just that it's very easy for them to become labiodental, and with good reason, and is what leads to the labial patterning described above. And as you will note on the page for Ewe, it makes a point that the labiodentals are articulated much more strongly than the bilabials, adding further support to my perception-based hypothesis. More work on the diachronics would be much welcomed, but I would suspect that the bilabial fricatives are relatively recent developments from the bilabial stops and the labiodentals older.

[Vijay]

I can't think of any actual linguists who are against Frislander on this.

[dɮ the phoneme]

This is only tenuously related, and probably better fit for the innovative usage thread, but I have a friend (a native AmE speaker) with unconditional f > φ. It's so typologically implausible that I'm not sure what to make of it.

[Tropylium]

Most of this thread seems to presume that bilabial vs. labiodental is some kind of surface phenomenon to be explained away, based on an underlying labial stop vs. labial fricative phonological structure. But note that the opposite analysis is possible as well: bilabial vs. labiodental as underlying versus stop vs. fricative as a surface phenomenon, so that [+obstruent +labiodental] → [+continuant].

The phonetic motivation remains the same, of course.

Worth noting is that to some extent this phenomenon applies also to velars versus uvulars. All sorts of languages have a setup with a velar stop versus a corresponding uvular fricative, but no corresponding uvular stop or velar fricative. For /k χ/ there are examples like German or Egyptian Arabic; for /g ʁ/ there's French, approximately all of Semitic, or half of all Turkic languages plus also various neighboring languages (Yukaghir, Kamassian, etc.). Georgian does both of these; various other Caucasian languages also have a variant with /k qχ/ and perhaps /kʼ qχʼ/.

The third option is to abstract away from POA versus MOA and to define the feature of "strident", which then triggers both frication and POA adjustment as surface phenomena. (Sibilants can be then grouped under this as well, so that e.g. /t tʲ ç/ are [-strident] while /ts tʃ ɕ/ are the corresponding [+strident] versions.)

[Frislander]

I can't think of any actual linguists who are against Frislander on this.

Are you implying I'm not yet an actual linguist? (Not a criticism, and it's true I guess, but given that Linguistics is my degree and intended career path it won't stay so for long).

[Vijay]

I can't think of any actual linguists who are against Frislander on this.

Are you implying I'm not yet an actual linguist? (Not a criticism, and it's true I guess, but given that Linguistics is my degree and intended career path it won't stay so for long).

No implication intended. I wasn't aware of any linguists in the conversation, but I also am not aware of any who would disagree.