Introduction:Communication skills and oral language competence constitute the cognitive and social scaffolding essential for academic achievement, emotional regulation, and peer integration in early childhood. Developmental Language Disorder (DLD) represents a persistent neurodevelopmental condition characterized by severe deficits in language acquisition, comprehension, and production in the absence of biomedical etiologies, intellectual impairment, or frank neurological damage. These deficits frequently manifest as compromised expressive vocabulary, syntactic delays, pragmatic incompetence, and restricted reciprocal dialogue. Contemporary neurocognitive evidence increasingly substantiates that linguistic manifestations in DLD do not exist in isolation; rather, they stem from pervasive underlying constraints across broad cognitive capacities. The Cattell-Horn-Carroll (CHC) theoretical framework conceptualizes human cognition as a multi-layered, hierarchical architecture comprising broad cognitive abilities that fundamentally underwrite linguistic processing. Specifically, deficits in central auditory processing (Ga) impede acoustic parsing and phonemic discrimination; limitations in verbal working memory (Gsm) restrict syntactic assembly and morphosyntactic retention; sluggish cognitive processing speed (Gs) disrupts rapid semantic access and conversational cadence; and impoverished crystallized knowledge (Gc) hampers lexical depth.

Concurrently, persistent communicative breakdowns impose severe relational strain within the family system, precipitating negative cycles of communicative frustration, maternal anxiety, and nonresponsive or directive parental styles. Although family involvement is empirically recognized as vital for communicative generalization, standard parent-mediated models frequently overburden parents by assigning them quasi-therapeutic teaching roles, accelerating parental burnout. Consequently, an integrative clinical framework that simultaneously rehabilitates CHC-grounded cognitive infrastructures and embeds structured communicative stimulation within a non-burdensome family interactive framework remains an urgent empirical imperative. Accordingly, this study aimed to develop and evaluate the effectiveness of a CHC-based cognitive-linguistic educational package integrated with family interactions on communication skills, oral language development, and parent-child relationship quality in students with DLD.

Method: This investigation utilized a quasi-experimental pretest-posttest-follow-up design with an active experimental group and an untreated control group. The target population comprised all elementary students aged 6 to 8 years diagnosed with DLD in Yasuj during the 2025–2026 academic year. Thirty eligible students were purposively sampled and randomly assigned into two parallel groups: an experimental group (n=15) and a control group (n=15). Inclusion criteria encompassed: meeting formal DSM-5 diagnostic criteria for DLD confirmed by a licensed speech-language pathologist; obtaining a general language quotient (SLQ) below 85 on the Test of Language Development; possessing a Nonverbal Index score ≥ 85 on the Wechsler Intelligence Scale for Children (WISC-IV) to rule out intellectual disability; and parental informed consent. Exclusion criteria comprised co-occurring sensory, motor, neurological, or autism spectrum disorders, or absence from more than two therapeutic sessions.The measurement battery included:

Diagnostic Clinical Interview: Administered to assess developmental history and ensure diagnostic purity according to DSM-5 criteria.

Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV): Employed to verify intact nonverbal intellectual functioning and cognitive baselines.

Test of Language Development-Primary: Third Edition (TOLD-P:3): Comprising subtests of picture vocabulary, relational vocabulary, oral vocabulary, grammatical understanding, sentence imitation, and grammatical completion, generating standard quotients for spoken language, listening, organizing, and speaking.

Communication Skills Questionnaire: A standardized multi-dimensional assessment evaluating nonverbal communication, verbal responsiveness, conversational initiation, listening competence, and socio-communicative adaptation on a 5-point Likert scale.

Pianta Parent-Child Relationship Scale (CPRS): A 33-item inventory measuring maternal perceptions of the relational dynamic across dimensions of closeness, conflict, and dependency.

The experimental group underwent twelve 30 minute intervention sessions delivered twice weekly by a clinical specialist. The curriculum targeted CHC cognitive processing strata systematically: acoustic figure-ground discrimination and phonemic manipulation (Ga); verbal span, forward or backward digit manipulation, and morphosyntactic buffering (Gsm); rapid automatized semantic naming and verbal fluency (Gs);and contextual narrative formulation(Gc);. Crucially, to avoid therapeutic exhaustion, family involvement followed a bidirectional-complementary framework wherein parents were guided to implement naturalistic communicative routines (e.g., communicative temptation, shared interactive reading, and responsive expansions) at home for 15 minutes daily. The control group received standard classroom schooling without intervention. Assessment data were collected at baseline, post-intervention, and at a one-month follow-up, and were analyzed via repeated measures analysis of variance (RM-ANOVA) using SPSS version 26.

Results: Statistical evaluation through RM-ANOVA demonstrated substantial, statistically significant intervention effects across all primary outcome variables in the experimental group compared to the control group (p<0.001). The main effect of time, the main effect of group, and the time × group interaction were all highly significant across communication skills, spoken language development, and parent-child relationship quality, demonstrating substantial partial eta-squared effect sizes . Pairwise comparisons utilizing Bonferroni post-hoc tests confirmed that improvements acquired from pretest to posttest in the experimental group were statistically robust (p < 0.001) and were fully preserved across the one-month follow-up assessment (p > 0.05 between posttest and follow-up), reflecting durable therapeutic gains. In contrast, the control group exhibited no statistically meaningful developmental alterations across the identical temporal trajectory (p > 0.05).

The empirical efficacy of this intervention operates through clear, interconnected cognitive-systemic mechanisms. By systematically remediating auditory processing bottlenecks (Ga), children developed acute acoustic parsing capabilities, which stabilized the perceptual encoding of transient grammatical morphemes. The expansion of verbal working memory capacity (Gsm) liberated mental workspace previously exhausted by basic decoding, allowing the dynamic retention and generation of hierarchical, multi-clause syntactic structures. Simultaneously, accelerating lexical retrieval speeds (Gs) truncated conversational latency, facilitating spontaneous verbal turn-taking.

These cognitive enhancements established the neural foundation necessary for functional communication. Concurrently, the structured family interactive component served as a developmental bridge: by cultivating reciprocal responsiveness, parental validation, and conversational scaffolding within daily domestic routines, negative relational conflict was supplanted by affective closeness and communicative self-efficacy. Thus, combining direct CHC-targeted cognitive training with daily relational opportunities creates an optimized, sustainable rehabilitation model that translates sub-lexical cognitive mechanics into rich, reciprocal communicative competence.