Introduction

Achieving native speaker fluency is a goal for many foreign language learners; nevertheless it is the one that is rarely achieved. The ability to be understood by native speakers requires not only mastery of grammar and vocabulary, but also the more subtle prosodic rules that influence the final output production. A poorer mastery of prosody leads at worst to a failure to be understood and at best to what is recognised as a foreign accent. Therefore, it is crucial to investigate the development of prosody in foreign language learners as a function of other measures of language proficiency. This chapter presents the results of research on Japanese prosody acquisition that examined the productive and perceptual abilities of learners who were studying Japanese as a second language.

Theoretical Background

It is a generally held belief that even very advanced second language learners, who can manipulate grammar and vocabulary very well, have moments when native speakers do not understand them because of their foreign accents. In some unfortunate circumstances, such foreign accents may cause social and/or interpersonal problems. For instance, in the workplace, a foreign accent might result in the loss of job opportunities (Sato, 1991). Moreover, a foreign accent can cause unintentional interpersonal problems in a non-native speaker's social life. Pickering (2001) reported that international teaching assistants were perceived as unsympathetic and uninvolved by their students because of their inappropriate prosodic patterns.

Accented speech also hinders understanding by listeners. Munro and Derwing (1995) examined foreign-accented speech in English produced by native speakers of Mandarin who were proficient enough to enter a university. The researchers showed that their subjects' speech intelligibility was lower when the speech was perceived to be accented. Munro (1998) further studied the effect of foreign-accentedness under natural noise listening conditions (cafeteria noise).