Background
Core vocabulary consists of a small set of high-frequency words (typically 200-400) that account for approximately 80% of words used in everyday communication. These words remain stable across communication partners, environments, and populations. Hebrew-speaking children with intellectual and developmental disabilities (IDD) demonstrate similar core vocabulary patterns: 1) The top 200 most frequently used lexemes (basic word forms) constitute 85% of the composite lexicon, 2) Function words dominate the most frequently used words, albeit with a slight preference for content words in children with IDD, and 3) Among the content words, children with IDD use more adverbs, while typically developing (TD) children use more verbs, with implications for AAC core vocabulary selection. Limited research exists on the core vocabulary developmental trajectory.
This presentation has a twofold purpose: 1) to describe our findings from a six-year core vocabulary study in Hebrew across ages within TD students, exploring overlap with English core word lists, and 2) to describe our Hebrew core vocabulary project implementation pilot that includes: the adaptation of Universal Core Vocabulary project modules and explicit speech-language pathologist group instruction to foster simple sentence construction.
Research Questions
Core Vocabulary Study: What is the size of the core vocabulary lexicon for Hebrew-speaking children across different age groups? How do core vocabulary words distribute between function and content words across age groups? How does Hebrew core vocabulary compare to English core vocabulary patterns?
Implementation Study: What is the efficacy of adapting universal core vocabulary project modules for Hebrew-speaking students with IDD and ASD?
Methodology
Following established psycholinguistic methods, we collected language samples from 12-15 typically developing Hebrew-speaking children at each age level (kindergarten through fourth grade) in two contexts: free play with peer interaction and structured play with adult mediation. All sessions were recorded, transcribed, and analyzed for lexeme distribution, frequency patterns, and cross-age overlap.
Building on these research findings, we conducted a preliminary pilot study in a special education school for students with IDD, involving 12 adolescent students (nine with IDD, three with IDD+ASD), three teachers, and three SLPs. The intervention included: 1) professional development for teachers and SLPs to implement the core vocabulary project across academic activities following adaptation of universal core vocabulary project modules, and 2) weekly SLP-led group sessions targeting core words and sentence construction using personal photos within meaningful contexts.
Results
Vocabulary Stability: Across all age groups, approximately 150-200 lexemes consistently accounted for about 80% of all words in both contexts. The top 20 lexemes represented ~40% of all words, the top 50 lexemes ~60%, the top 100 lexemes ~72%, and the top 200 lexemes ~82%. Chi-square tests showed no significant differences between kindergarten and fourth-grade distribution patterns (p > 0.05), indicating stability despite developmental progression.
Function vs. Content Words: The top 20 most frequent lexemes predominantly consisted of function words across all ages, remaining stable from kindergarten through fourth grade.
Cross-linguistic Comparison: An 88% overlap (32/36 words) existed between Hebrew core words and universal core vocabulary, suggesting potential for cross-linguistic AAC design principles while maintaining language-specific considerations.
Preliminary Implementation Results: Social validity questionnaire results suggested positive trends: 67% of educational staff reported apparent improvements in student motivation during language activities, while 83% noted wider vocabulary use. The majority observed potential improvements in sentence construction ability, and 67% expressed confidence in continuing core word implementation.
Implications for Practice
AAC System Design: The identified Hebrew core vocabulary lists may guide vocabulary selection for Hebrew-speaking children, along with access to fringe vocabulary and students’ personal words.
Intervention Approaches: The preliminary positive responses to the adaptation of the core vocabulary project suggest this approach may merit further investigation, particularly when combining explicit SLP instruction with teacher professional development.
Cross-linguistic Applications: The substantial overlap of Hebrew core vocabulary with English core vocabulary tentatively suggests that certain AAC design principles and strategies might apply across languages, while recognizing Hebrew-specific features.
Future Directions: This research provides initial evidence for Hebrew core vocabulary stability and preliminary evidence of intervention effectiveness. However, the implementation study’s small sample size and pilot nature necessitate larger-scale replication studies before drawing definitive conclusions. Future research should include controlled studies with larger samples and standardized outcome measures.
References
Binger, C., Harrington, N., & Kent-Walsh, J. (2024). Applying a developmental model to preliterate aided language learning. American Journal of Speech-Language Pathology, 33(1), 33-50.
Erickson, K., Geist, L., Hatch, P., & Quick, N. (2019). The universal core vocabulary [Technical report]. Center for Literacy & Disability Studies, University of North Carolina at Chapel Hill.
Savaldi-Harussi, G., & Uziel, S. (2025). Frequency of Hebrew word usage by children with intellectual and developmental disabilities: Implications for AAC core vocabulary. Augmentative and Alternative Communication, 41(1), 78-86.
