Morpho-lexical development in language impaired and typically developing Hebrew-speaking children from two SES backgrounds

The study investigated the impact of language impairment and environmental deprivation on Hebrew morpho-lexical development across the school years. Participants were 659 grade school and middle school Hebrew-speaking students—typically developing and language impaired, from mid-high and from low socio-economic status (SES). They were all administered three derivational morphology tasks designed to elicit verbs, adjectives and derived abstract nouns. Each response was scored in three different ways: as a whole word, and according to its base (root or stem) and affixal (pattern or suffix) morphemes. Findings revealed three systematic hierarchies. First, the typically developing mid-high SES group always scored the highest, the language impaired low SES group always scored the lowest, while the typically developing low SES and the language impaired mid-high SES groups lay in-between. Second, verbs were the easiest category across all study groups, whilst adjectives and derived abstract nouns proved to be more affected by population type. Third, affixal morpheme always scored lower than base morpheme, with persistent gaps between the typically developing mid-high SES group and all other groups. Altogether, results show that language development is impeded extensively by both language impairment and SES factors, suggesting that in the long run, innate and environmental factors may have similar implications on morpho-lexical development.