Language Teaching Research Quarterly

High-Variability Phonetic Training (HVPT) has demonstrated effectiveness in second language (L2) acquisition. This study utilizes a meta-analysis to explore the influence of high variability on learning L2 pronunciation and identifies the factors that moderate this impact. The studies were collected using a keyword search in the SCOPUS database. In total, our meta-analysis incorporated 18 primary studies that presented results obtained from experimental and control group designs, encompassing a total of 22 effect sizes. The results of our meta-analysis revealed that the overall effect size of HVPT on L2 pronunciation was medium (g = 0.77). Specifically, the effect size was large for consonant sounds and lexical tones, particularly pronounced when utilized by advanced learners. For beginners, the effect size was medium. The context in which the training was conducted also played a role, with a medium effect size observed when sentences were used. Additionally, the number of talkers involved in the study influenced the effect size, with a medium effect size found when 5 to 8 talkers were included. In other cases, the reported effect sizes were either small or non-significant.