A contraction of Hoc illud. Thus, hoc-ill', ho'-il, o'il, oïl, oï, oui

So Hoc illud is simply an overlong way of saying "yes"?

Could one of our resident Latin scholars translate, please?

And what's "yes" a shortening of, then?

It seems very strange that simple affirmation should ever require more than one word, especially when one of them has more than one syllable.