Old Norse þrettán

← Old English þreotīene (cognate)

← Proto-Germanic *þritehun (inherited)

← Old High German drīzehan (cognate)

← Old Frisian thretīne (cognate)

← Old Saxon thriutein (cognate)

→ Old English þreotiene (cognate)

→ Danish tretten (derived)

→ Faroese trettan (inherited)

→ Westrobothnian trettan (inherited)

→ Old Swedish þrættan (inherited)

→ Icelandic þrettán (derived)

→ Norwegian Bokmål tretten (derived)

→ Norwegian Nynorsk tretten (derived)

→ Norn trettin (derived)

→ Old Saxon thriutein (mention)

→ Elfdalian trettǫ (derived)

→ Swedish tretton (derived)