Where does “fourti” come from?

fourti (Middle English) comes from Old English fēowertiġ, from Proto-West Germanic *feuwar tigiwi — forty.

Ancestry of “fourti”, step by step

StepLanguageWordMeaning
1Old Englishfēowertiġforty
2Proto-West Germanic*feuwar tigiwiforty
Every word from Proto-West Germanic *feuwar tigiwi →Every word from Old English fēowertiġ →