Can you explain the use of the Y in the word Israel?

In the original Hebrew, the name is: Yisrael, meaning we have wrestled with man and angels and have been victorious. I have no idea who and when it was transliterated to: Israel, but there is no significance to that transliteration. All I can add, is that different Jewish communities in various places over the 2,000 year exile, pronounced different letters a little differently (usually caused by external influence of local foreign languages), and this is sometimes seen in transliterations (like Shlomo became Solomon, Avraham became Abraham, Yitzchak- Isaac, Rivka-Rebecca).