I am becoming a bit concerned that my otherwise bright 2.6 DS has no clue about his colours. He is very articulate, knows his numbers, has been picking up key words from books for months and understands some complex concepts but just cannot grasp colours. It is something I regularly bring up during play but it just doen't seem to go in, he remembers the names but ask him what colour two yellow objects are he will say eg. one is red and the other green, even familiar objects like bananas and oranges. At his 2yr check the HV didn't seem worried but I kind of thought that 6mnths later he would have picked it up, should I be worrying? does anyone know anything that can help?