every child is different, i remember my daughters forst birthday, she could talk clear as a bell and was running round like a nutter!! she seemed to be fairly advanced on everything!
i would say at that age they should be understanding colours, tho they only pick up what they see and hear, have you actually tried encouraging it?
buy some colourful things and play games with them naming all the colours, when you go out point at things and call them by their colours, it will all help
goodluck