Production and maternal report of 16- and 18-month-olds' vocabulary in low- and middle-income families.

PURPOSE To compare maternal report of children's vocabularies on the MacArthur Communicative Development Inventories Words and Gestures form (CDI:WG; Fenson et al., 1993) with spontaneous production data in both low- and middle-income families. METHOD As part of a longitudinal investigation, language samples were gathered from 23 mother-child dyads based on Stoel-Gammon's (1987) protocol for the Language Production Scale when the children were 16 and 18 months of age. The mothers also completed the CDI:WG at both visits. The words that the children produced were compared with those the mothers reported on the vocabulary checklist, with family income and vocabulary size as grouping factors. RESULTS Maternal reporting did not differ as a function of socioeconomic status but did increase from 16 to 18 months. CONCLUSIONS The vocabulary differences observed on the CDI:WG for children from low-income families do not appear to be a reflection of inaccurate maternal reporting. Further research is needed to determine whether these findings will generalize more broadly.