| For 13 parent/child dyads, we looked at how the quality (noun-related inflectional morphemes and noun phrase usage) and quantity of caregiver input directed to infants from 7 to 18 months of age was related to noun vocabulary expression in those same children at 1, 2, and 3 years of age. We expected that the frequency of morpheme use and the presence ofelaborated noun phrases would be related to a larger later expressive noun vocabulary sizeincreasing with infant age. Correlation, regression, and effect size values resulted in some statistical and clinical significance on infant noun vocabularysize as demonstrated through parent usage of noun morphology and noun phrases. Findings from the study can be used by speech-language pathologists to strengthen caregiver education regarding the impact of caregiver noun morphology and noun phrase use on expressive noun vocabulary development. Clinical implications, study limitations, and future directions are discussed. |