There are words that have "j" where in most languages it would be pronounced like romaji "y".
Take for example "Jesus", "Jehovah", "John". It should be pronounced "Yesus", "Yehovah", "Yohn".
Slavic languages and Esperanto have "j" sound like romaji "y" so if you'd write "Jessica", it would be pronounced "Yessica". Now, why isn't that in English? Why does also in Spanish "j" sound like "h"? How did this transformation start?
Also, why is "halelujah" not written like it's pronounced: "haleluyah"? Ironically "trojan" is not just an English word, but a Croatian word too that sounds like "troyan". Why is the "j" there if it sounds like "g" and not "y"? Why isn't "Troy" "troj"? I'm so confused! When is it "j" and when is it "y"!?