Where does “al-” come from?

al- (Middle English) comes from Old English eall-, from Proto-Germanic ala- — compound form of *allaz.

Ancestry of “al-”, step by step

Step	Language	Word	Meaning
1	Old English	eall-	all, every; pan-; completely, totally; very
2	Proto-Germanic	ala-	compound form of *allaz

al- — Etymology, Origin & Word History | Etymology Explorer