I believe that Kleio was pronounced KLY-o in Greek. At least wikipedia gives that pronunciation.
― Anonymous User 10/5/2021
2
The correct pronunciation is as follows in Greek: K (as in key), L (as in let), ee (as in see), AW (as in law), so thus Klee-AW. I could see this easily Anglicizing to Klee-oh or CLAY-oh in English.