Voicing and devoicing processes in Farsi-speaking children with typical and protracted phonological development

Background and aim: One of the main factors that differentiate child speech from adults' is the phonological processes that happen in child language, including voicing and devoicing. The present study aims to consider and compare the quality of voicing/devoicing errors occurring in Farsi-speaking children with protracted and typical phonological development. Moreover, this study compares voicing/devoicing errors of typical Farsi-speaking children with the voicing/devoicing errors of children speaking other languages. Method: Five children with typical phonological development (2;6-4;0) and 5 children with protracted phonological development (4;6-6) participated in this qualitative cross-sectional study. The typical children were collected from nursery schools and the protracted children were recruited from speech therapy clinics in Karaj. They were chosen via convenience sampling method. Their voicing/devoicing errors were investigated using Naming-picture task (Farsi phonology test with pictures) wherein each child asked to produce 133 single words. Results: Devoicing errors were distributed more widely than voicing errors in typical and atypical phonological development, especially in word-final position. The typical children participating in this study rarely displayed word-medial devoicing; however, atypical children illustrated several cases of it. Word-initial and medial voicing were observed in both groups of children; however, word-final voicing was merely detected in atypical children. Conclusion: Results revealed that the differences observed in voicing/devoicing processes between children with protracted and typical phonological development is due to the different hierarchy of markedness and faithfulness constrains in their internalized grammar. Furthermore, there are major similarities in voicing process between typical Farsi-speaking children and typical children speaking other languages.