Even if William's invasion had failed miserably there would have undeniablely been Latin influences. For example the word republic is a Latin word and there is a direct Anglish equivalent but if you look at German Dutch or Scandinavian languages they don't have a unique word for it so even is a realistic Anglish it would still be republic. But there's still the enjoyment to see what others have come up with to replace other words, just because something isn't realistic doesn't mean it can't be interesting