Language areas are distinguished by colour, and the distinction is reduced in family view. Support for users with colour vision deficiency could be added by giving each language area textured patterns in addition to colours.
Just a prototype right now for the sort of thing I was envisioning. I find the current solution pretty ugly and somewhat slow, but I think this'll do for now.
A future pattern I have in mind is tiling polygons.
Language areas are distinguished by colour, and the distinction is reduced in family view. Support for users with colour vision deficiency could be added by giving each language area textured patterns in addition to colours.