Where does “-edh” come from?

-edh (Cornish) comes from Middle Welsh -eð, from Proto-Celtic *-iyā, from Proto-Indo-European -éh₂.

Ancestry of “-edh”, step by step

StepLanguageWordMeaning
1Middle Welsh-eð—
2Proto-Celtic*-iyāForms abstract nouns from adjectives
3Proto-Indo-European-éh₂—

Words derived from “-edh”

Every word from Proto-Indo-European -éh₂ →Every word from Middle Welsh -eð →Every word from Proto-Celtic *-iyā →