A conceptual category approach to the study of the comprehension of natural language is presented as an alternative to previous approaches made solely in terms of information gain or specific linguistic variables. Elementary school children between the ages of 6 and 11 years were given a referent identification task to test their comprehension of 32 sentences containing a representative selection of the linguistic devices used in English for comparing quantities of discrete objects. The results showed that at grade 1 level, children still have remarkably poor comprehension of these devices. Comprehension of comparatives increases significantly until at least grade 3, and comprehension becomes easier at least until the end of elementary school as indicated by significantly shorter response latencies. This study also clarified other aspects of the comprehension of these linguistic devices. For example, it was found that comparisons made in terms of equality using "positive" adjectives (e.g., "as large as") were significantly easier than comparisons using "negative" adjectives (e.g., as small as"). A significant interaction between age and the relative difficulty of negation was found. Implications of this approach for research in developmental psycholinguistics, second language teaching, and the preparation of materials are discussed. (Author/DD)