Native English-speaking (NS) listeners evaluated effects of three types of instruction (segmental accuracy; general speaking habits and prosodic factors; and no specific pronunciation instruction) on speech of three groups of English-as-a-Second-Language (ESL) learners. Sentences were recorded and extemporaneously produced narratives at beginning and end of 12-week course. In blind rating task, native-speaker listeners judged randomized sentences for accentedness and comprehensibility. Findings are discussed. (Author/JL)