Scheduling practice sessions to create a spacing effect enhances L2 pronunciation and fluency. Such manipulation of practice sessions is also conducive to better L2 vocabulary and grammar retention. Blocking and interleaving are task manipulation methods widely discussed in recent times as effective methods of L2 teaching. The present study measured the difference in the effect of these two methods on the enhancement of English pronunciation and fluency and on the retention of English vocabulary and grammar by keeping Indian adolescent ESL learners (N=64) under blocked and interleaved conditions during a three-month-long speaking proficiency training program in English. Three tests were conducted during the program to assess the differences in speech performance. Speech samples collected from the participants at different stages of the program were evaluated in pronunciation, fluency, vocabulary, and grammar by four external assessors. The test scores collected in these tests were analyzed using repeated measures ANOVA. Although the blocked group produced oral responses in English that exhibited a bit more flexibility, appropriacy, and complexity in word choice as well as sentence construction and less phonological error and hesitation, the study recorded no statistically significant differences in the effect of these two methods on the English speaking proficiency of the participants.