The English language has 26 letters in its alphabet. Most of the letters have a distinct sound to them but there are few letters that have several different sounds to them depending on the word that it is in. Most of the consonants have one sound that they make. The letter J has one sound in the English language. Therefore when an
English speaker sees a word with the J in it, they would pronounce that word the same way that they are used to pronouncing each letter of that word. However when someone learns a language that is different than their native language they learn how to pronounce each letter but there are exceptions to the rules. So they may pronounce the jays silently and all Spanish words because they don’t realize that was an exception to the rule.