As quickly as you can, say aloud the color of the following words(time yourself):
REMEMBER: Say the color of the word. Not the word itself...
BLUE GREEN RED PINK YELLOW WHITE ORANGE RED GRAY PURPLE YELLOW PURPLE BROWN BLUE GRAY BROWN GREEN RED PINK BLUE ORANGE GRAY YELLOW WHITE PINK RED BROWN ORANGE WHITE PURPLE GREEN BROWN PURPLE GRAY BLUE PINK ORANGE GREEN YELLOW WHITE
Did it take longer? It should have. Now do the same test with a young child who can't read yet. You'll be surprised at the results...