Actually, if you do an internet search you will learn that the terms are ambiguous - at least in usage. I don't know if all journals have coordinated their usage, but when people speak of them, you will get different opinions.
So, does bi-monthly mean twice a month or every two months. Opinions will differ, unfortunately.
Quarterly is almost always meant to imply four times per year. Maybe always.
But the more important question is how this affects review times. I doubt that it has any affect at all. A paper will take what it takes to get a decent set of reviews and an editorial decision.
More likely a journal with more issues per year than another, either has more submissions, or specializes in longer papers. If papers are long, there may be (in the print world) less room in a given issue for several papers. If papers are short there may be more submissions.
If you want a quick decision, write a shorter paper. Write a clearer paper. Write an exciting paper. Of course a terrible paper will also get a quick decision, but not one you'd prefer.