Two studies were conducted, with three-to-five-year-olds, to assess the relationship between language comprehension and production and the development of quantity concepts. The asymmetry of acquisition of adjectives, "big" and "little," was also assessed, as well as differences in the acquisition of the underlying concepts. In Experiment 1, it was demonstrated that the child's ability to understand relative magnitude differences and quantitative equality precedes the comprehension of the words "big,""little," and "same." In Experiment 2, it was demonstrated that verbal cues involving relational terminology did not facilitate problem solving for the three-year-olds but did for four-year-olds. Also, successful problem solution preceded the ability to produce language about quantity. In general, asymmetries between the adjectives representing positive and negative poles of a dimension were found to be present in linguistic tasks rather than in conceptual ones. The results suggest that, for the quantity concepts, language and thought function independently in the early stages of concept development of the young child, but become increasingly related with development. (Author)