Brown and orange are different brightness levels of the same colour. Brown is dark orange and orange is light brown. Yet people experience brown and orange as separate colours, because we have separate words for it, while we experience light blue and dark blue as different brightness levels of the same colour, because both are called “blue”.
The same is true for English too.
Brown and orange are different brightness levels of the same colour. Brown is dark orange and orange is light brown. Yet people experience brown and orange as separate colours, because we have separate words for it, while we experience light blue and dark blue as different brightness levels of the same colour, because both are called “blue”.