Jakubinskij's law
Jakubinskij's law, or Meyer–Jakubinskij's law, is a sound law that operated in the Croatian Chakavian dialect in the 12th and 13th centuries, named after Lev Jakubinskij who discovered it in 1925, and sometimes also after K. H. Meyer who expanded and refined the rule in 1926. Jakubinskij's law governs the distribution of the mixed Ikavian–Ekavian reflexes of Common Slavic yat phoneme, occurring in the Middle Chakavian area.