This research contrasted deaf and hearing students' interpretive knowledge of English sentences containing numeral quantifier phrases and indefinite noun phrases. A multiple-interpretation picture task methodology was used to assess 305 participants' judgments of the compatibility of sentence meanings with depicted discourse contexts. Participants' performance was assessed on the basis of hearing level (deaf, hearing) and grade level (middle school, high school, college). The deaf students were predicted to have differential access to specific sentence interpretations in accordance with the relative derivational complexity of the targeted sentence types. Hypotheses based on the pressures of derivational economy on acquisition were largely supported. The results also revealed that the deaf participants tended to overactivate pragmatic processes that yielded principled, though non-target, sentence interpretations. Collectively, the results not only contribute to the understanding of English acquisition under conditions of restricted access to spoken language input, they also suggest that pragmatic factors may play a broad role in influencing, and compromising, deaf students' reading comprehension and written expression.