Meillet's law is a Common Slavic
accent law, named after the French Indo-Europeanist Antoine Meillet
, who discovered it.
According to the law, Slavic words have a circumflex on the root vowel (i.e., the first syllable of a word), if that word had a mobile accent paradigm
, regardless of whether the root had the Balto-Slavic acute register
* acute on Lithuanian ''gálvą'', accusative singular of mobile-paradigm ''galvà
'' 'head', vs. circumflex in Slavic (Serbo-Croatian ''glȃvu
'', Slovenian ''glavô
'', Russian ''gólovu
* acute on Lithuanian ''sū́nų
'', accusative singular of mobile-paradigm ''sūnùs'' 'son', versus circumflex in Slavic (Serbo-Croatian ''sȋn
'', Slovenian ''sȋn
Meillet's law should most probably be interpreted as polarization of accentual mobility in Slavic, due to which accent in the words with mobile accentuation had to be on the first ''mora'', instead on the first syllable (in places in paradigm with initial accent). This is the reason in the words belonging to mobile paradigms in Slavic accent shifts from the first syllable to the proclitic, e.g. Russian accusative singular of mobile-paradigm ''gólovu'', but ''ná golovu'' 'on the head', Serbo-Croatian ''glȃvu'', but ''nȁ glāvu''.
Meillet's law appears to not have taken effect in the infinitive of verbs. This form normally had ending accent in mobile paradigms, but some Balto-Slavic mobile verbs had root accent in the infinitive as a result of Hirt's law
. In Slavic, these infinitives retained their acute accentuation, thus creating next to the present ''*gryzèšь''.
Such verbs appear synchronically to be a mixture of accent paradigms ''a'' and ''c''.