This study aimed to investigate the characteristics and developmental phenomena apparent in Japanese learners of English with their raters' perspectives in terms of fluency which has been recognized as a major factor in judging non-native speakers' proficiency. The following temporal indices demonstrated strong relationships with the raters' scores on fluency: total number of syllables including/excluding dysfluency, total number of words, and total speaking time including pause time. The three indices can be useful when confined to Japanese students. With regard to pauses and hesitations, the university students exhibited results comparable to other participants; however, the locations and lengths of pauses at a phrase boundary alone gave evidence that they paused at grammatical junctures. (Contains 6 tables and 2 figures.)