AD&D Monstrous Manual (1993)

White dragons, the smallest and weakest of the evil dragons, are slow witted but efficient hunters. They are impulsive, vicious, and animalistic, tending to consider only the needs and emotions of the moment and having no foresight or regret. Despite their low intelligence, they are as greedy and evil as the other evil dragons.

The scales of a hatchling white dragon are a mirror-like glistening white, which makes them virtually invisible against a snowy background. As the dragon ages, the sheen disappears, and by the time it reaches the very old stage, scales of pale blue and light gray are mixed in with the white.

White dragons speak their own tongue, a tongue common to all evil dragons, and 7% of hatchling white dragons have an ability to communicate with any intelligent creature. The chance to possess this ability increases 5% per age category of the dragon.