As an innovative digital platform, voice blogging offers learners opportunities to improve their speaking performance; however, the impact of voice blogging on speaking complexity, accuracy, and fluency (CAF) has been insufficiently explored, especially in the English as a foreign language (EFL) context. Adopting a sequential explanatory mixed-methods approach, the current study was set to examine the impact of voice blogging on EFL learners’ speaking performance in general, and speaking CAF in particular. Using convenience sampling, two intact classes comprising thirty-nine upper-intermediate EFL learners were selected from a private language institute. They were randomly assigned to an experimental (voice blogging) group with 18 EFL learners and a control (non-voice blogging) group with 21 EFL learners. During a 14-week term, both groups participated in topic-based EFL speaking presentation tasks. The voice blogging learners engaged in EFL speaking practice through voice blogging, whilst the non-voice blogging learners practised EFL speaking in face-to-face interactions. Using two samples of Cambridge IELTS speaking tasks for collecting the required quantitative data, we applied paired sample t-test, one-way ANCOVA, Man Whitney U, and Wilcoxon signed-rank tests for analysing the data. The qualitative data included individual semi-structured interviews carried out with the voice blogging learners to find out more about their attitudes and perceptions towards the voice blogging course. Paired sample t-test and one-way ANCOVA indicated that the voice blogging course developed the EFL learners’ speaking performance and outperformed its non-voice blogging counterpart in that regard. Man Whitney U and Wilcoxon signed-rank tests revealed that the voice blogging instruction developed the EFL learners’ speaking complexity and accuracy, but it did not significantly affect the EFL learners’ speaking fluency, and the voice blogging learners also outperformed the non-voice blogging learners in speaking complexity and accuracy. The interview findings indicated that the learners emphasised the effective role of voice blogging tasks in enhancing their engagement in speaking activities. The findings imply that incorporating voice blogging into EFL speaking instruction positively affects EFL learners’ speaking performance, specifically in terms of speaking complexity, accuracy, and engagement. However, it might be necessary to complement voice blogging courses with additional fluency-based activities and strategies to compensate for the lack of development in speaking fluency.
