I don't think it does. Chinese, Japanese and Korean had been using vertical writing for centuries, only switching to horizontal ones around 20th century for int

I don't think it does. Chinese, Japanese and Korean had been using vertical writing for centuries, only switching to horizontal ones around 20th century for interoperability with Western writing (such as math or chemical formulae). Mongolian script, from the link presented here, has actually switched from being horizontal to being vertical (under influence of Chinese).