Thal et al. : Vocabulary and Grammar Measure for Spanish-Speaking Toddlers 1087 Donna Thal San Diego State University San Diego, CA and University of California, San Diego Donna Jackson-Maldonado University of Querétaro Querétaro, Mexico Dora Acosta San Diego State University San Diego, CA The validity of the Fundación MacArthur Inventario del Desarrollo de Habilidades Comunicativas: Palabras y Enunciados (IDHC:PE) was examined with twenty 20- and nineteen 28-month-old, typically developing, monolingual, Spanish-speaking children living in Mexico. One measure of vocabulary (number of words) and two measures of grammar (mean of the three longest utterances and grammatical complexity score) from the IDHC:PE were compared to behavioral measures of vocabulary (number of different words from a language sample and number of objects named in a confrontation naming task) and one behavioral measure of grammar (mean length of utterance from a language sample). Only vocabulary measures were assessed in the 20-month-olds because of floor effects on the grammar measures. Results indicated validity for assessing expressive vocabulary in 20-month-olds and expressive vocabulary and grammar in 28-month-olds. KEY W ORDS: parent report, language development, Spanish, vocabulary, grammar Validity of a Parent-Report Measure of Vocabulary and Grammar for Spanish-Speaking Toddlers Journal of Speech, Language, and Hearing Research • Vol. 43 • 1087–1100 • October 2000 • ©American Speech-Language-Hearing Association 1092-4388/ 00/ 4305-1087 P arent report has had an off-again on-again relationship with the field of developmental psycholinguistics. Over the last 10 years, with the development of new instruments (Fenson et al., 1993, 1994; Rescorla, 1989), the methodology has re-emerged and is being widely used for both clinical and research purposes. The usefulness of these instruments has spawned development of similar instruments in a number of other languages, including American Sign Language (Reilly, 1992), Chinese (Tardif, Gelman, & Xu, 1999; Wu, 1997), Dutch (Lejaegere, in process), Finnish (Lyytinen, Poikkeus, & Laakso, 1997; Lyytinen, Poikkeus, Leiwo, Ahonen, & Lyytinen, 1996), French (Poulin-Dubois, Graham, & Sippola, 1995), German (Grimm, Doil, Müller, & Wilde, 1996), Hebrew (Meital, Dromi, Sagi, & Bornstein, submitted), Icelandic (Thordardottir, 1996), Italian (Caselli & Casadio, 1995), Japanese (Ogura, Yamashita, Murase, & Dale, 1993), Korean (Pae, 1993), Spanish (Fernandez & Umbel, 1991; Jackson-Maldonado, Thal, Marchman, Bates, & Gutierrez-Clellen, 1993), and Swedish (Berglund & Eriksson, 1996). For the United States and Mexico, one of the most important new in- ventories is the Fundación MacArthur Inventario del Desarrollo de Habilidades Comunicativas (Jackson-Maldonado, Bates, & Thal, 1992). In this paper we report the validity of parent report of vocabulary and grammar for 20- and 28-month-old children using the Palabras y