Proto-Slavic *tęžьkъ

→ Belarusian цяжкі (inherited)

→ Bulgarian тежък (inherited)

→ Czech těžký (inherited)

→ Old Church Slavonic тѧжькъ (inherited)

→ Lower Sorbian śěžki (inherited)

→ Westrobothnian tong (mention)

→ Upper Sorbian ćežki (inherited)

→ Latin taedeo (cognate)

→ Lithuanian tingus (cognate)

→ Macedonian тежок (inherited)

→ Old Norse þungr (cognate)

→ Old East Slavic тѧжькъ (inherited)

→ Polish ciężki (inherited)

→ Russian тяжкий (inherited)

→ Rusyn тяжкый (inherited)

→ Serbo-Croatian težak (inherited)

→ Serbo-Croatian тежак (inherited)

→ Slovak ťažký (inherited)

→ Slovene težek (inherited)

→ Silesian ciynżki (inherited)

→ Ukrainian тяжкий (inherited)