Welsh iaith

← Breton yezh (cognate)

← Proto-Brythonic *jeiθ (inherited)

← Proto-Celtic *yextis (inherited)

← Old High German jehan (cognate)

← Proto-Indo-European *yek- (inherited)

← Cornish yeth (cognate)

← Latin jocus (cognate)

← Old Irish icht (cognate)

← Middle Welsh ieith (inherited)

← Tocharian A yask (cognate)

→ English joke (cognate)

→ Welsh cyfieithu (affix)

→ Welsh tafodiaith (compound)

→ Welsh ieithydd (affix)

→ Welsh ieithydd (affix)

→ Welsh llediaith (prefix)

→ Welsh meta-iaith (prefix)

→ Welsh dwyieithog (affix)

→ Welsh ieithadur (suffix)

→ Welsh bratiaith (compound)

→ Latin iocus (cognate)