@skeofli,
skeofli wrote:In this context what is a mark
It is a way of carrying additional information about a word in the way it is spelled.
For instance, in the Spanish example, the way a noun is spelled indicates its gender.
In the Japanese example, you can tell from a noun's spelling whether it is supposed to be a subject or an object.
skeofli wrote:and what does English mark?
To be honest, I don't remember. It's been a long time since I've taken an English class.