I see his point about direction of written characters in my #4583 above. The western or 'Romance' languages all seem to have evolved as left to right. I don't really know about the eastern written languages. Some languages read top - down; there may be other variations in complex written texts; those vertical 'lines' could proceed right to left or left to right. I have not studied that.
Yeah, I did think of the few languages that are verticle. Seems like I even remember one that reads bottom to top :)