en گفتار درمانی Speech therapy پژوهشي Original Research Articles <div style="text-align: justify;"><strong>Objectives: </strong>The current study mainly aimed at studying the effect of Knowledge of Result (KR) feedback timing and result-estimation opportunity before receiving delayed KR on learning a new speech motor skill in monolingual healthy adults.&nbsp;<br> <strong>Methods:</strong> Thirty-nine Persian healthy adults were randomly divided into three groups. Each group received immediate KR, delayed KR (after eight seconds), or delayed KR (after eight seconds) with self-estimation of the result in the delay interval. All three groups received verbal KR feedback. Participants were trained to produce a French phoneme (/ɪn/) in the context of words in four training sessions. The correct production of the target phoneme was judged by a bilingual Persian-French examiner holding an academic degree in French language teaching. Later, a transfer test and two retention tests were administered. The two retention tests were administered one day and two weeks after the last training session respectively.&nbsp;<br> <strong>Results:</strong> The effect of feedback timing on motor performance and motor learning was examined by repeated-measures ANOVA. Performance in both acquisition and retention phases was significantly different between groups (P=0.04 for both phases). One-way ANOVA was used to investigate the transfer of learning (P=0.001). Tukey test results indicated that the groups 1 and 2 were different in both acquisition and retention phases and all three groups were different in transfer test.<br> <strong>Discussion:</strong> The results showed that the immediate KR is beneficial for the acquisition phase, and delayed KR is more beneficial for the retention and transfer tests compared with immediate KR.</div> Motor learning, Knowledge of results, Result estimation, Delayed feedback, Motor speech, Immediate feedback 171 180 http://irj.uswr.ac.ir/browse.php?a_code=A-10-814-1&slc_lang=en&sid=1 Fateme Karimi karimi232@yahoo.com 0000-0003-0501-8077 No Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Majid Soltani majidsoltanist@gmail.com 0000-0003-3827-1431 Yes Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Mohammad Jafar Shaterzadeh Yazdi shaterzadeh.pt@gmail.com 0000-0002-5707-302X No Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Negin Moradi Neginmoradist@gmail.com 0000-0002-5141-1307 No Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. Saman Shahriari samanshahriari69@yahoo.com 0000-0002-5212-4924 No Department of Language and French Literature, Faculty of Letters and Humanities, Shahid Chamran University, Ahvaz, Iran. Seyed Mahmoud Latifi sml1381@yahoo.com 0000-0001-8989-5397 No Diabetes Research center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.