Why did Clement of Alexandria say that the name of Jesus, Iesous, has a Greek origin, not a Hebrew one? Did Clement of Alexandria actually believe that Jesus was called Iesous in Greek and that it wasn't a translation of the Hebrew?

Wikipedia cites the Catholic Encyclopedia's entry on the Origin of the Name of Jesus Christ:


  [Cyril of Jerusalem], however, appears to agree with Clement of Alexandria in considering the word Iesous as of Greek origin (The Pedagogue III.12)


But this doesn't seem to be addressed in that section of The Pedagogue.
From the Wikipedia article in the original post:


  The English form of the name "Jesus" is derived from the Latin Iēsus, which in turn comes from the Greek Ἰησοῦς (Iēsoûs). The Greek is a Hellenized form of the Hebrew name Yēšua (ישוע), which is in turn a shortened form of Hebrew Yehōšua (יהושע) or "Joshua" in English.


"Iesous" is not a Greek translation of the Hebrew "Yehosua", because it isn't a Greek word that means the same thing as the Hebrew word.  It is, rather, a transliteration, an adaptation of the word itself to the Greek alphabet and Greek word-building conventions.  (An example of translation would be Christos, from which we take the word "Christ."  It means the same thing in Greek as Messiah means in Hebrew, despite being very different actual words.)

It's not uncommon for words to be slightly mangled in transliteration, especially between languages with different alphabets.  For example, have you ever been to a Chinese restaurant and seen Peking duck on the menu? If you look at a map of China today, you won't find a place called "Peking" anywhere, because in the 1950s China came up with a new system of transliterating Chinese names to the Latin alphabet to more closely match the way the names are supposed to sound, and these days the city that used to be known as Peking in English is now written as "Beijing."