If a syllable ends in a vowel (not a diphthong) followed by a laryngeal, then the accent is retracted onto that syllable if it originally fell on the following syllable. The law applies to the original PIE accent placement, but after levelling of PIE mobile-accented paradigms into end-stressed paradigms. It also applied before the epenthesis before syllabic sonorants.
In words with a (Balto-Slavic) mobile accent paradigm, the accent was retracted from a medial onto the initial syllable. In Proto-Slavic, a similar analogical change caused the retraction of the accent onto a preceding unaccented clitic, such as a preposition.
Short vowels (*a, *e, *i, *o, *u) are lengthened before unaspirated voiced stops (*b, *d, *g, but not *ǵ). The newly lengthened vowel receives the "acute register". The law may only have applied to vowels that were followed by a stop in the same syllable.
（立陶宛语）If a non-acuted accented syllable is followed by an acuted syllable, the accent shifts forwards onto the acuted syllable. This split the Balto-Slavic fixed accent paradigm into Lithuanian paradigms 1 and 2, and the mobile accent paradigm into paradigms 3 and 4.
If a syllable was non-acute and accented, the accent was advanced onto the following syllable. The originally accented syllable retains its length. The change was prevented if the word had a mobile accent paradigm.
Yers (the vowels *ь and *ъ) became "strong" or "weak" in an alternating pattern, depending on their position in a word. A yer was weak unless the next syllable contained a weak yer, then it became strong. Weak yers were eventually lost, while strong yers were lowered and became other vowels.
In words with a mobile accent paradigm, if the first syllable is accented with a rising (acute) accent, it is converted into a falling (circumflex) accent.
If a word-final syllable was long falling (circumflex) accented, the accent was retracted onto the preceding syllable. The originally accented syllable is shortened, and the newly-accented syllable receives a "neoacute" accent. This change applied after Dybo's law, and often "undid" it by shifting the accent back again.
后缀 *j alternates with *ij depending on the syllable weight (length) of the preceding morpheme. *j appears after "light" or "short" morphemes, which consist of a single syllable ending in a short vowel and a single consonant. *ij appears elsewhere, including all morphemes with more than one syllable.
When it is an ablaut alternant of *e, the vowel *o is lengthened and (after merging) becomes *ā when it stands at the end of a syllable.
In all words or word-groups of four or more syllables bearing the chief accent on a long syllable, a short unaccented medial vowel was necessarily syncopated, but might be restored by analogy
