Grounded in the biopsychosocial models of expressive language in autism spectrum disorder (ASD) and fragile X syndrome (FXS), this dissertation included two novel studies that examined the role of biological (i.e., physiology), psychological (i.e., autistic traits, anxiety symptoms, and child affect) and social (i.e., communication partner…

This article introduces the NFL7 (Nuclear Family List 7), a list of the 2,887 most frequent "nuclear" word families, that is, families that include just the most frequent family members and exclude those that constitute less than 7% of family occurrences. The NFL7 was developed by using a dedicated computer program, the Nuclear List…

Generalization is the ability to apply regularities to novel instances, for example, correctly guessing that the plural for the novel English word 'wug' should be 'wugs'. Early language learners make overgeneralization errors like 'mouses', applying regularities beyond their attested uses. Theories concerned with the question of how learners learn…

This thesis examines whether native, heritage, and L2 speakers of Spanish engage a morphological layer of representation in the processing of inflected words, and whether they do so with both regularly- and irregularly-inflected words. Also examined is whether this tendency towards compositional (i.e. morphological rule-based) processing is…

Although children with Autism spectrum disorders (ASD) show significant variation in language skills, research on what type(s) of language profiles they demonstrate has been limited. Using growth-curve analyses, we investigated how different groups of young children with ASD show increases in the size of their lexicon, morpho-syntactic production…