With Spanish being my first language, this confused me to no end. I constantly found myself reviewing my uni assignments to add a comma before the last item of

With Spanish being my first language, this confused me to no end. I constantly found myself reviewing my uni assignments to add a comma before the last item of a list. This, that, and that other thing. which I would write as Esto, eso y eso otro. ...In Spanish. Never really put any effort in understanding why, I just took it on face value and now I know.