Dybo's law


Dybo's law, or Dybo–Illich-Svitych's law, is a Common Slavic accent law named after Russian accentologists Vladimir Dybo and Vladislav Illich-Svitych. It was posited to explain the occurrence of nouns and verbs in Slavic languages which are invariantly accented on the inflectional ending. The latter is seen as an innovation from the original Proto-Balto-Slavic accent system, in which nouns and verbs either had invariable accent on the root, or "mobile" accent which could alternate between root and ending in the inflectional paradigm.

Overview

According to the law, the accent was shifted rightward from a non-acute syllable to the following syllable if the word belonged to the fixed accentual paradigm. This produced the difference between the later accent classes A and B. The length of the previously-accented syllable remains.
The preservation of the original length is the primary source of pre-tonic length in the later Slavic languages, because inherited Balto-Slavic vowel length had previously been shortened in pre-tonic syllables, without a change in vowel quality. This caused the phonemicization of the previously automatic quality variations between short and long vowels — e.g. short *o vs. originally long *a.

Examples

Word-final syllables with the Balto-Slavic acute register were shortened and then lost the acute, before the time Dybo's law operated. It could then be lengthened again by Van Wijk's law, producing a long non-acuted vowel. Therefore, when the accent shifted onto a final syllable, the new accent was either circumflex or short, but never acute.
When the new accent was circumflex or fell on a yer, the accent was subsequently shifted leftward again by Ivšić's law, resulting in a neoacute accent:
When the new accent was short and Van Wijk's law did not apply, then Ivšić's law had no effect, and the accent remained on the second syllable:
The acute was preserved in non-final syllables, however. Thus, when shifting onto a non-final syllable, all three accents were possible, depending on the state of the syllable before Dybo's law operated. Ivšić's law in turn operated on forms where the new accent was circumflex, but not where it was acute or short. Compare:
Dybo's law was entirely prevented in cases of initial accent in words belonging to the mobile accent paradigm. In such forms, Meillet's law resulted in loss of the acute register on the root, so that all initial-accented mobile forms were in principle susceptible to Dybo's law. Jasanoff argues that such forms had a special "left-marginal accent", which was not affected by Dybo's law the way the "lexical accent" of fixed-accent paradigms was. Thus:
In the valence theory, followed by the Moscow accentological school but otherwise not generally accepted, Dybo–Illich-Svitych's law is not considered single one-time change, but rather a succession of changes. It is described as a series of rightward accentual shifts in various Late Proto-Slavic dialects, with successive removal of accent drift prohibitions. There are two prohibitions, common to all Late Proto-Slavic dialects:
Early Proto-Slavic is also considered a shift of accent on internal syllables, as well as on some endings with a dominant aсutе – AP, AP, AP. This process refers to the Fortunatov–de Saussure's law.

Dialects of the III group

Dialects of the III group are associated with the tribal division of Slovenes. In part, this can be traced to the historically attested self-names of speakers of this type of dialects: Slovenians, Slovakians, Slovincians, Novgorod Ilmen Slavs. Archaeologists associate the Prague-Korchak culture with the Slovenes and with its continuation the Luka-Raikovetskaya culture, which currently contains Belarusian and Ukrainian Polesians dialects. Apparently, the culture associated with the tribal unification of the Severians dates back to this same culture.
Commons phenomena:
Non-commons phenomena:
*dòbrȍta*tvòrîlo*sǫ̃dîlo*gròbȃ*mǫ̃drȍstь*kǫ̃tȃ*tvòrȋtь*sèlā̋*sǫ̃dȋte*krĩdlā̋*nòsĩtь*ža̋ba̋*pra̋vi̋ti
IIIА*dobro̍ta*tvori̍lo*sǫdi̍lo*groba̍*mǫdro̍stь*kǫta̍*tvo̍ritь*se̍la*sǫ̍dite*kri̍dla*no̍sitь*ža̍ba*pra̍viti
IIIB*dobro̍ta*tvori̍lo*sǫdi̍lo*groba̍*mǫdro̍stь*kǫta̍*tvori̍tь*se̍la*sǫ̍dite*kri̍dla*no̍sitь*ža̍ba*pra̍viti
IIIC*dobro̍ta*tvori̍lo*sǫdi̍lo*groba̍*mǫdro̍stь*kǫta̍*tvori̍tь*sela̍*sǫ̍dite*kri̍dla*no̍sitь*ža̍ba*pra̍viti
IIID*dobro̍ta*tvori̍lo*sǫdi̍lo*groba̍*mǫdro̍stь*kǫta̍*tvori̍tь*sela̍*sǫ̍dite*kri̍dla*no̍sitь*ža̍ba*pra̍viti

Comparison with Fortunatov–de Saussure's law

is a sound law very similar to Dybo's that affected Lithuanian. Like Dybo's law, it caused a rightward shift of the accent from non-acuted syllables and a split in the original accentual paradigms. There are some differences, however: