This article explores the effects of different task repetition schedules on English learners’ oral fluency in terms of speed, breakdown, and repair indices using a PRAAT script to enhance objectivity and consistency in the assessment of learner performances. A total of 90 freshmen participated in the experiment and were divided into three groups: the blocked repetition group, the interleaved repetition group, and a control group. This study adopted a pre- and post-test design. After the learners repetitively practiced the problem-solving tasks for three weeks, their improvement was measured by a new task of the same type. The analyses of speed, breakdown, and repair in learners’ oral performance reported that the experimental groups outperformed the control group in fluency measurement. Specifically, the interleaved repetition group was advantageous compared with the blocked repetition group, except for the silent pause numbers. The findings not only support the interleaving effects and enrich the line of task repetition research but also have pedagogical implications in that introducing interleaved practice in real classrooms is beneficial to L2 speaking enhancement.