Fateme Karimi - Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Majid Soltani - Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Mohammad Jafar Shaterzadeh Yazdi - Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Negin Moradi - Musculoskeletal Rehabilitation Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Saman Shahriari - Department of Language and French Literature, Faculty of Letters and Humanities, Shahid Chamran University, Ahvaz, Iran.
Seyed Mahmoud Latifi - Diabetes Research center, Health Research Institute, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.

Objectives: 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.  Methods: 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.  Results: 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=۰.۰۴ for both phases). One-way ANOVA was used to investigate the transfer of learning (P=۰.۰۰۱). Tukey test results indicated that the groups ۱ and ۲ were different in both acquisition and retention phases and all three groups were different in transfer test. Discussion: 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.

Motor learning, Knowledge of results, Result estimation, Delayed feedback, Motor speech, Immediate feedback