Where does “dw-ene-” come from?

dw-ene- (Proto-Indo-European) comes from Proto-Indo-European deu-, from Middle Welsh deu, from Proto-Brythonic *dow, from Proto-Celtic *duwo, from Proto-Indo-European dwóh₁ — two.

Ancestry of “dw-ene-”, step by step

StepLanguageWordMeaning
1Proto-Indo-Europeandeu-lack, fail; to injure, destroy, burn; to do,...
2Middle Welshdeutwo
3Proto-Brythonic*dowtwo
4Proto-Celtic*duwotwo
5Proto-Indo-Europeandwóh₁two
Every word from Proto-Indo-European dwóh₁ →Every word from Proto-Celtic *duwo →Every word from Proto-Brythonic *dow →