The current study presents findings from a mixed-methods study of investigating the self-regulatory role of private speech (self-talk) on students’ translation quality. The aim of the study was to validate the adapted version of a self-verbalization questionnaire. The construct validity and reliability of the scale were supported by the CFA which revealed that all items reached the acceptable fit thresholds and had high reliability. The study utilized two phases of analysis. In the quantitative analysis, 151 undergraduate English translation students participated in this study. Two questionnaires including validated self-verbalization scale and self-regulation accompanying a text were distributed among the students to determine the influence of the self-regulatory role of private speech on translation quality. The results demonstrated that the students who used more private speech had a better translation quality that shows the self-guidance role of private speech. In the qualitative phase of the study, 21 English translation students attended an interview. The focus of the interview was on the potential functions of the self-regulatory role of private speech in translation. The results indicated that most students apply private speech as a facilitator of the difficult task. Retention and evaluation were also among the most often applied strategies by the students. Manuscript profile