Investigation and Comparison of the Grammatical Profile of Persian-Speaking Hearing-Impaired Children with Hearing Children

Auditory function plays a pivotal role in natural language development, and damage to it can lead to serious disorders in the acquisition of grammar. This research was conducted with the aim of delineating the grammatical profile of Persian-speaking hearing-impaired children and its quantitative and qualitative comparison with hearing children using a standardized test. This study was descriptive-analytical and was carried out using a field method. The statistical population consisted of hearing-impaired children in Baghcheban schools in Tehran, from which 10 hearing-impaired second-grade elementary school children were selected as the experimental group and 10 hearing children were selected as the control group via available sampling. The research tool was the standardized "Grammatical Expression" test by Haras Abadi and colleagues (2014), which included 40 items for assessing 20 different grammatical structures. Data were analyzed using descriptive statistics and the non-parametric Mann-Whitney test in SPSS software. Data analysis showed a significant difference between the overall performance of the two groups in the domain of grammatical expression. Specifically, hearing-impaired children showed the most problems in using complex syntactic structures such as adverbial relative clauses, causative constructions, and contrastive pronouns, as well as in inflectional categories such as verb tense, mood, and aspect, verb agreement, and attached pronouns. The findings indicate the existence of a much weaker grammatical profile in Persian-speaking hearing-impaired children compared to their hearing peers. This weakness was particularly evident in complex syntactic structures and sensitive inflectional categories. The results emphasize the necessity of designing and implementing early, targeted, and intensive speech therapy interventions that specifically focus on explicit teaching of these structures. Such interventions can greatly help reduce the linguistic gap and improve the communication skills of these children.