I think it's derived from the same source as German, but I always get confused when trying to understand language sources.
I just found
this diagram, which doesn't make it any clearer, but looks like it could be fun to examine at some point.
Yiddish, English, Dutch and German are all in the bottom left, all derived from West Germanic roots at various levels.
Of course, with Schedule coming from a Latin word, I guess none of those pronunciations are much help.
:/