It's really just a conditioned shift of accent one syllable to the right, which split underlyingly accented morphemes into self- and post-accenting ones. Sometimes, the shift doesn't happen or is reversed due to certain properties of the vowel which the accent was supposed to move onto. This creates a new kind of mobile accent which alternates between two neighboring syllables instead of between the beginning and the end of the word.gestaltist wrote: ↑16 Dec 2019 09:30I'm nowhere close to an expert but being a native speaker of a Slavic language, my intuition is that this might be due to (some? all?) post-accenting morphemes losing their vowel when not final. I wonder what Zekoslav would have to say about that.
As for losing their vowel, this isn't necessarily connected to being a post-accenting morpheme but one very common morpheme which looses its vowel (Common Slavic *-ьcь) is post-accenting indeed.
This is good material for a new post, although I'm deliberating whether I want to say something on (Balto-)Slavic accent system's development from the Proto-Indo-European one since that's a topic where there's lots of speculation and little certainty (Basically some sound correspondences have been found but no sound laws have been posited which can explain them without tons of exceptions and ad hoc analogy).
EDIT: here's an actual example from a Croatian dialect (length and tone are ignored for convenience and only place of accent is marked) which shows what patterns each kind of morphemes creates.
We have popraviti 'to fix', ponoviti 'to repeat' and potrošiti 'to spend'
(The forms are, in order: infinitive, supine, present 1 2 3 sg. 1 2 3 pl., l-participle m f n sg. m f n pl.)
/poˈprɑvim, poˈprɑviʂ, poˈprɑvi, poˈprɑvimo, poˈprɑvitæ, poˈprɑviju/
/poˈprɑvil poˈprɑvilɑ poˈprɑvilo poˈprɑvili poˈprɑvilæ poˈprɑvilɑ/
Accent is consistently on the root, root is analysed as self-accenting strong morpheme.
/poˈnovim, poˈnoviʂ, poˈnovi, poˈnovimo, poˈnovitæ, poˈnoviju/
/ponoˈvil, poˈnovilɑ, ponoˈvilo, ponoˈvili, ponoˈvilæ, poˈnovilɑ/
Accent alternates between the root and the immediately following syllable, root is analysed as post-accenting strong morpheme.
/potroˈʂim, potroˈʂiʂ, potroˈʂi, potroʂiˈmo, potroʂiˈtæ, potroʂiˈju/
/ˈpotroʂil, potroˈʂilɑ, ˈpotroʂilo, ˈpotroʂili, ˈpotroʂilæ, potroˈʂilɑ/
Accent alternates between the initial syllable and a suffix, root is analysed as a weak morpheme.