Where does “ipsi-” come from?

ipsi- (English) comes from Latin ipse, from Proto-Italic *e(s)peso.

ipsi- (English): self, same

Definitions

Step	Language	Word	Meaning
1	Latin	ipse	himself, herself, itself, the very, the actual;...
2	Proto-Italic	*e(s)peso	—

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