German zäh

← English tough (mention)

← Middle High German zæhe (inherited)

← Proto-West Germanic *tą̄h(ī) (inherited)

← Old High German zāhi (inherited)

← Old High German zāh (mention)

← Proto-Indo-European *denḱ- (root)

← Low German taag (cognate)

← Dutch taai (cognate)

→ English tough (cognate)

→ German zähflüssig (compound)

→ German zähfließend (compound)

→ German superzäh (prefix)

→ Luxembourgish zéi (cognate)

→ Dutch taai (cognate)

→ Saterland Frisian toai (cognate)