[For the complete volume, "CALL and Professionalisation: Short Papers from EUROCALL 2021 (29th, Online, August 26-27, 2021)," see ED616972.]This study investigated whether a translation tool (Microsoft Translator -- MT) and its built-in speech features (Text-To-Speech synthesis -- TTS -- and speech recognition) can promote learners' acquisition in pronunciation of English regular past tense "-ed" in a self-directed manner. Following a pretest/posttest design, we compared 29 participants' performances of past "-ed" allomorphy (/t/, /d/, and /id/) by assessing their pronunciation in terms of phonological awareness, phonemic discrimination, and oral production. The findings highlight the affordances of MT regarding its pedagogical use for helping English as a Foreign Language (EFL) learners improve their pronunciation.