Polnoglasie

Polnoglasie 

a specific lexical-phonetic feature of the modern East Slavic languages. In Russian, polnoglasie is reflected in the sequences of the letters oro, olo, ere, and elo in words of Common Slavic or East Slavic origin, such as korova (“cow”), moloko (“milk”) boloto (“swamp”), bereg (“bank,” “shore,” “coast”), and zhelob (“gutter”). Polnoglasie resulted from the reshaping of the proto-Slavic diphthongs or, ol, er, and el between consonants (tort, tolt, tert, telf), which was influenced by a tendency for open syllables. In the South Slavic languages and in Czech and Slovak these sequences changed to trat, tlat, tret, and tlet, as in the modern Bulgarian krava, blato, briag, and mliako. In West Slavic languages they changed to trot, tlot, tret, and tlet, as in the modern Polish krowa, błoto, brzeg, and mleko.