Investigation of Inconsistent Phonological Disorder in Persian-Speaking Children Aged 5 to 7: A Neural and Cognitive Linguistics Perspective

Eftekhary Far, Sadegh; Estaji, Azam; Khalifeh Loo, Sayed Farid

doi:10.22059/jolr.2025.390884.666911

Document Type : Research Paper

Authors

¹ Ph.D. Candidate in Cognitive Linguistics at Ferdowsi University of Mashhad, Mashhad, Iran.

² Department of Linguistics, Dr. Ali Shariati Faculty of Literature and Humanities, Ferdowsi University of Mashhad, Mashhad, Iran.

³ Department of Linguistics, University of Sistan and Baluchestan, Zahedan, Iran.

https://doi.org/10.22059/jolr.2025.390884.666911

Abstract

Employing a Cognitive Linguistics framework—specifically Langacker's Cognitive Grammar, Rosch's Prototype Theory, and Hickok and Poeppel's dual-streams model—this research explores Inconsistent Phonological Disorder (IPD) in Persian-speaking children aged 5-7 years. Speech data from seven children with IPD were analyzed using both quantitative and qualitative methods, revealing the following results: First, 73% of phoneme production errors showed a relationship between instability (e.g., /k/ to /t/ substitutions) and a deficit in phonological encoding at the formulation stage of the Levelt model. Second, syllabic simplification in the form of CVC to CV structures was the dominant strategy for reducing cognitive load in children with IPD (mean of CV syllables = 0.68). Third, dysfunction in the dorsal stream, especially in the parietal-premotor connections, was identified as a neural factor in the instability of phoneme production. Cross-linguistic comparisons showed that in Persian, IPD errors mainly involve phoneme substitution, while in languages with complex phoneme clusters, such as English, the reduction of these clusters predominates. This study suggests that efficient IPD treatment should focus on strengthening phoneme cues and improving the function of dorsal stream neural circuits. In addition to enriching the neurocognitive literature on IPD, the findings of this study provide guidelines for the developing integrated treatment protocols. Therefore, IPD is considered a multifaceted deficit resulting from the dysfunctional interaction of cognitive, linguistic, and neural systems. Its treatment requires a comprehensive approach targeting both mental representations of phonemes and the associated neural circuits. It is suggested that therapeutic exercises be designed based on Rosch's theory, focusing on strengthening the representation of exemplars through frequent words. Also, neuromodulation methods such as transcranial direct current stimulation (tDCS) may prove useful and effective in improving premotor cortex function and the transfer of phonological schemas.

Keywords

References

Ball, M. J. (2016). Principles of Clinical Phonology: Theoretical Approaches. Routledge Publisher. USA.

Damico, J.S., Muller, N. & Ball, M. J. (2021). The Handbook of Language and Speech Disorders, Second Edition. John Wiley & Sons Ltd.

Dodd, B. (2010). Differential diagnosis & Treatment of Children with Speech Disorders. Second Edition. Whurr publishers: London & Philadelphia.

Eftekhary Far, Sadegh. (2016). Investigation and comparison of some phonological processes of 4 to 7-year-old Persian-speaking children with consistent and inconsistent phonological disorder based on Optimality Theory. Master's thesis, University of Sistan and Baluchistan. [In Persian].

Fakar Qaramelki, F. and Mehri, A. (2017). Investigating the effect of the basic words approach in the treatment of unstable phonological disorder: a case report. Scientific Research Quarterly of Rehabilitation Medicine, 8(3): 288-279. [In Persian]

Hickok, G. (2009). The Functional Neuroanatomy of Language. Physics of Life Reviews, 6(3), 121-143.

Hickok, G. & Poepple, D. (2007). The cortical organization of speech processing. Nature Reviews Neuroscience 8: 393-402.

Hickok, G. & Poepple, D. (2000). Toward a functional neuroanatomy of speech perception. Trends in Cognitive Sciences, 4, 131-138. [PubMed: 10740277].

Jonathan, Littlemore. and John R. taylor (2014). An introduction to the theories of cognitive linguistics (along with some practical aspects). (translated by Parsa Bamshadi and Shadi Ansariyan). Isfahan: Kavoshyar Publications (1395). [In Persian].

Johnson, Mark. (1987). The body in the mind: the physical basis of meaning, imagination and reasoning (translated by Jahanshah Mirzabaigi). Tehran: Agah Publications (1398). [In Persian].

Langacker, Ronald. (2013). Cognitive Grammar (translated by Jahanshah Mirzabaigi). Tehran: Agah Publications (1397). [In Persian].

Levelt, W. J. M. (1999). Producing spoken language: A blueprint of the speaker. In P. Hagoort & C. Brown (Eds.), Neurocognition of language processing (pp. 83–122). Oxford University Press.

Marchetti, P. T., Dalcin, L.M., Balen, S. A. & Mezzomo, C. L. Temporal auditory processing and the distinctive feature of children with phonological disorder. Rev. CEFAC, 24(3).

Nilipour, Reza. (2016). Cognitive linguistics: the second epistemological revolution in linguistics. Tehran: Hermes Publications. [In Persian].

Pascoe, M., Stackhouse, J & Wells, B. (2006). Persisting Speech Difficulties in Children: Children Speech & Literacy Difficulties. Book 3. Wiley Publisher, London.

Saur, D., Kreher, BW., Schnell, S., Kummerer, D., Kellmeyer, P., Vry Ms, and others. (2008). Ventral & Dorsal pathways for Language. Proc Natl Acad Sci USA, 100: 18035-40.

Shushtari Zadeh, F. (2019). Coordination of production manner in Persian speaking children with normal and disordered phonological development. Linguistic Research Journal, Isfahan University, 12, 22(1). [In Persian].

Shushtari Zadeh, F. (2018). Voicing and voiceless processes in Persian-speaking children with normal and impaired phonological development. Research paper on Persian language teaching to non-Persian speakers, 8, 2(18). [In Persian].

Soleymani, Z., Shakeri, N., Zarifian, T. & Kamali, M. (2015). Investigation Phonological Awareness in Persian-Speaking Children with Phonological Disorders. Middle East Journal, 2(4), e32200.

Sosa, A. V., et al. (2022). Cross-linguistic patterns in phonological disorders. Journal of Speech Disorders, 45(3), 75–89.

Sweller, J. (2011). Cognitive load theory. In Psychology of learning and motivation: 55, 37–76. Academic Press.

Tafaroji Yeganeh, M. (2015). Comparative study of phonological disorders of bilingual children with Down syndrome in Kurdish and Persian languages. Scientific Research Journal of Ilam University of Medical Sciences: 24(5). [In Persian].

Tourville, J. A., & Guenther, F. H. (2023). The DIVA model: Neural mechanisms of speech motor control. NeuroImage, 270, 120–135.

Waring, R., Rickard Liow, S., Dodd, B. & Eadie, P. (2022). Differentiating Phonological delay from phonological disorder: Executive function performance in preschoolers. International Journal of Language and Communication Disorders.

Language Research

Investigation of Inconsistent Phonological Disorder in Persian-Speaking Children Aged 5 to 7: A Neural and Cognitive Linguistics Perspective

References

References

Volume 16, Issue 2 - Serial Number 31
March 2026
Pages 37-58

Investigation of Inconsistent Phonological Disorder in Persian-Speaking Children Aged 5 to 7: A Neural and Cognitive Linguistics Perspective

References

References

Volume 16, Issue 2 - Serial Number 31March 2026Pages 37-58

Volume 16, Issue 2 - Serial Number 31
March 2026
Pages 37-58