As I was contemplating the Norwegian word "del," which means "part" or "portion," it occurred to me that there is the same root in Russian, and that it means the same thing. I looked up "del" and "делить" (the verb formed from the root "дел"), and here's what I got:
From Middle Low German dēl, deil, from Old Saxon dēl, from Proto-Germanic *dailą, *dailiz (“part, portion, deal”).
From Proto-Slavic *děliti (“to divide”), from Proto-Balto-Slavic *doyl-, from Proto-Indo-European *dʰayl-, *dʰoyl-. Cognates include Old English dǣlan (English deal) and Lithuanian dailyti.
How do these chains get constructed, and why don't these two lead to the same common ancestor?