hebrew: "hey, we don't use vowels, so here's this name that is y<vowel>s<vowel>s<vowel>
english: "let's make this particular joshua jesus"
spanish: "let's make all joshuas jesus"
Yeshu’a became Jesus via Greek, where it was Iesous. Then Iesus in Latin, and then the convention came to be to use J for initial I when it is followed by a vowel.
Joshua is usually Yehoshu’a, of which Yeshu’a is a contracted form. So, really he should be Josh Christ.