> Although Ruby element is basically a Japanese thing It's commonly used in textbooks for different Chinese languages. I have ministry of education textbooks f

> Although Ruby element is basically a Japanese thing It's commonly used in textbooks for different Chinese languages. I have ministry of education textbooks from Taiwan, and ruby characters are used for both Hokkien and Mandarin (the Hokkien one has two different ruby character scripts which is quite visually busy). I would imagine it would be handy for Hindi learners as well. And probably hundreds of other languages, though I can't speak if it is used.