How do consonant clusters originate?

Question

I tried finding some information on this topic but there isn't a lot of information out there. The only things I could find is that it could originate from deletion of vowels between consonants. Are there any other ways? And why do some languages develop towards having more consonant clusters and other don't. Are there any circumstances that facilitate that? I also read that for example in Slavic ,,me,, regularly yielded mle. Are there any other phonological rules like that? Trying to figure out how languages like Georgian got the way they are.

Answer 1

There are a ton of ways that consonant clusters can be created: here is an outline of the main ways. The question is how does the sequence (V,#)C(V,#) end up with CC. First, there is morpheme concatenation, adding a C-final prefix to a C-initial root. You can avoid CC by inserting a vowel, deleting one of the consonants, or changing a consonant into a vowel. Otherwise you now have CC.

Second, you might start with VCVCV, and delete the vowel in the middle: VCCV. Same possible choices about eliminating the consonant cluster. Third, you might lengthen a consonant between vowels, giving VC:V, then latter split the single long segment into two, giving VCCV. Fourth, you might convert a vowel directly to a consonant, e.g. CVV → CCV or VVC → VCC.

The only explanation for these changes as a whole is the unsatisfactory truth that this is within the realm of what languages can do. You can usually uncover a satisfying answer for more specific example. For example, the change /tua/ → [tkʷa] in Kinyarwanda historically starts as a simple prosodic rule rearranging syllables to avoid VV, so /tua/→[twa] (a consonant cluster). Then there is a dissimilation where [pwa] becomes [pɰa], next [pγa]→[pga]→[pka]. The change /kantele/ → [kantle] in Estonian is because of a rule deleting unstressed vowels in an open non-final syllable. The change /ridiriʃa/ → [ddiriʃa] in Logoori is because r and d both involve raising the tongue, and speakers started to drop the gesture of lowering the tongue for [i] between the two consonants, thus the consonant cluster was created.

Answer 2

Just to add in more observed possibilities and potentialities for such phenomenon.

1. C1V1C2V2(C3) → C1C2V2(C3)

2. De-voicing on voiced plosive consonants (for examples, Austro-Daic, Cantonese, at least some Austroasiatic) [g] → [k{w;j;h(aspiration)}] Note: [w] ↔ [u], [j] ↔ [i]

3. De-nasalisation on nasal consonants (for examples, Austro-Daic) [n] → [nd]; [m] → [mb];

4. Split of nasalisation and bilabialisation (for examples, Austro-Daic, Cantonese) [m] → [n{w;ɯ}]; De=nasalisation → [{r;l}{w;ɯ}]; Note: [{w;ɯ}] ↔ [u], [j] ↔ [i]

5. Extension of bilabialisation (for examples, Austronesian) [m] → [mw]; Note: [w] ↔ [u], [j] ↔ [i]

6. Presumed sound compression of 2 syllables (normally with the same coda) (for examples, Cantonese) [baŋ] + [laŋ] → [blaŋ]; [kwik] + [lik] → [kwlik];