Proto-Slavic *ęzykъ

→ Czech jazyk (inherited)

→ Kashubian jãzëk (inherited)

→ Lower Sorbian jězyk (inherited)

→ Upper Sorbian jazyk (inherited)

→ Macedonian јазик (inherited)

→ Polish język (inherited)

→ Polabian jǫzĕk (inherited)

→ Old Prussian insuwis (cognate)

→ Serbo-Croatian jezik (inherited)

→ Slovak jazyk (inherited)

→ Ukrainian язик (inherited)

→ Old Czech jazyk (inherited)