Although there have been many studies examining the acquisition of grammar in Japanese as a second language (L2) (e.g., Nagatomo, 1993; Noda, Sakoda, Shibuya, & Kobayashi, 2001), discourse analysis research on the L2 acquisition of Japanese discourse structure is still in its infancy. This study examines how L2 learners organize their spoken discourse, and how spoken discourse by learners of Japanese changes as they develop proficiency, from intermediate to advanced levels, using interview and casual conversation data. The study found that although mid-intermediate learners used zero referential forms with ease, they still had difficulty effectively utilizing pronouns and demonstratives to refer to the preceding context. In contrast, high-intermediate learners showed an increase in the utilization of both demonstratives and pronouns. As for personal referents, omitting personal referential forms was easily employed by the intermediate level of Japanese, and the use of zero personal referential forms increased as at higher proficiencies. In addition, the study revealed that 'sentences without subjects' and 'full sentences' were the two most frequently used structures analyzed in the casual conversation data. Also, with higher proficiency, full sentences decreased while sentences without subjects increased. Furthermore, the results showed that the higher the learners' proficiency was, the more frequently they used postposing, a specific feature in spoken Japanese. Different types of postposing were used depending on the learner's proficiency level. In sum, there were gradual shifts in use of the referential forms and discourse structures depending on the learner's proficiency. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]