In learning the meaning of a new term, children need to fix its reference, learn its conventional meaning, and discover the meanings with which it contrasts. To do this, children must attend to adult speakers--the experts--and to their patterns of use. In the domain of color, children need to identify color terms as such, fix the reference of each one, and learn how each is used in the language. But color is a property, and terms for properties appear to be more difficult to grasp than do those for objects, actions, and relations. Although children find some domains easier to learn than others, they depend in each case on the expertise of adult speakers.