The MacArthur Inventario del Desarrollo de Habilidades Comunicativas: Primeras Palabras y Gestos (IDHC) is a widely-used parent report measure for infant Spanish language comprehension. The IDHC was originally created for use with infants of Mexican background. According to the U.S. 2017 census, however, about 37% of U.S. Hispanics are not of Mexican origin. In Miami-Dade, a large county in South Florida, 98% of Hispanics do not identify Mexico as their country of origin. IDHC use in mixed Hispanic communities such as Miami may be problematic due to differences in dialect and object labels. This study explored whether excluding IDHC words flagged as unknown or not commonly used by adults from mixed Hispanic communities affects bilingual infants' vocabulary size. Data were collected from Hispanic 16-month-old infants (N = 27; females = 13) from a mixture of Latin American backgrounds residing in Miami, FL, USA, and compared to archival data from the IDHC Mexican norming sample (N = 60; females = 31). Findings indicate significant differences in the rate of comprehension between the two samples with infants from mixed Latin American backgrounds demonstrating lower rates of comprehension for words flagged as unknown/uncommon. Moreover, Spanish vocabulary scores for infants from mixed Hispanic communities were significantly lower compared to the Mexican norming sample. Use of total vocabulary score (i.e., Spanish + English) attenuated these issues in administrating the IDHC to bilingual infants from mixed Hispanic communities. Results suggest that comprehension of some IDHC words is influenced by Hispanic family background. These preliminary findings highlight potential issues in IDHC administration that require further investigation in additional samples spanning the full age range of the IDHC and from a range of socioeconomic backgrounds to effectively tune how we assess infant Spanish language comprehension to cultural differences.
Keywords: bilingualism; development; infants; language.