INFANT-TODDLER DEVELOPMENT: AN INTRODUCTION ELENA PLANTE The University of Arizona
KEY WORDS: Language development
Through advances that promote survival of medically fragile infants, and changes in the public laws that encourage early intervention, speech-language pathologists and audiologists are being asked to provide services for increasing numbers of infants and toddlers. Many of these professionals find that they must serve this expanding population with minimal training and limited clinical tools (Crais, 1995; Dunn, van Kleeck, & Rossetti, 1993). This is occurring at the same time that new information is leading to a reconceptualization of infant sensory, perceptual, cognitive, and linguistic development. Much of this information has the potential for shaping our understanding of normal and impaired communication. Researchers are now identifying the cognitive, perceptual abilities, and elements of motor development that support and promote language and communication. For example, information on prenatal hearing has been exploited by researchers like DeCasper and Spence (1986) to show how the prenatal sound environment can shape postnatal infant responses to their communicative environment. Others have concentrated on how infants perceive speech and the cues they use to facilitate comprehension of speech (e.g., Jusczyk, 1995; Werker, Lloyd, Pegg, & Polka, 1996). This research is highlighting the importance of early sensitivity to prosodic contours and frequency-of-occurrence effects as important to early receptive language development. Comparable gains have been made in understanding the infant’s development of expressive language skills as well. Recently, investigators (Boliek, Hixon, Watson, & Morgan, 1996) documented the developments of normal speech-breathing that support concurrent development of vocalizations. Others (e.g., Oller, 1994) have examined the transitions from the first sounds to the first words and identified components that appear to Address correspondence to E. Plante, Department of Speech and Hearing Sciences, P.O. Box 210071, The University of Arizona, Tucson, AZ 85721-0071. Phone: (520) 621-5080; Fax(520) 6219901; E-mail: ,[email protected]
J. COMMUN. DISORD. 32 (1999), 191–193 © 1999 by Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010
0021-9924/99/$–see front matter PII S0021-9924(99)00012-X
predict later problems in expressive language development. This type of research promotes identification of critical components for normal language acquisition, and consequently provides a “roadmap” of potential points of breakdown for children who fail to acquire language normally. This issue includes a series of papers that were originally presented at the 1998 American Speech-Language-Hearing Association Research Symposium on Infant-Toddler Development, sponsored by the National Institute on Deafness and Other Communication Disorders. The series begins with a discussion by Bates concerning the neurobiological context within which children develop and language is acquired. She argues against an “innateness” account of language acquisition. Instead, she offers a framework for understanding how experience mediates the ultimate functioning and the adaptability of the brain for acquiring language, even in the face of early damage. The next two papers examine early receptive and expressive language skills that begin to emerge within the first year of life. Jusczyk explores the evidence that infants use multiple cues to segment the ongoing acoustic stream of speech into words and phrases. These early skills may play a significant role in the acquisition of both lexical items and the syntactic structure of a language. Oller, Eilers, Neal, and Schwartz turn to the domain of expressive language in their examination of early babbling and its potential clinical utility in identifying infants at risk for disabilities. These papers are followed by a discussion by Paul, who expands upon these themes. She points to literature concerning how input to the child may assist children’s early comprehension and on the outcome of children with early expressive language delays. Early receptive and expressive language development occurs in the context of a child who is also developing cognitively and motorically. These aspects are explored in papers by Meltzoff and by Boliek and Lohmeier. Meltzoff asserts that infants and toddlers begin life with representational capabilities and provides evidence to support early memory skills as well. Boliek and Lohmeier highlight Meltzoff’s work and expand the discussion to include aspects of motor development that have applications to early speech motor control. Information on the earliest emerging capabilities of infants and toddlers is critical for identifying behaviors that foreshadow developmental disorders. Furthermore, this type of information is able to support the development of intervention procedures that are effective in increasing the communicative skills of increasingly young children.
REFERENCES Boliek, C.A., Hixon, T.J., Watson, P.J., & Morgan, W.J. (1996). Vocalization and breathing during the first year. Journal of Voice, 11, 373–390.
Crais, E.R. (1995). Expanding the repetoire of tools and techniques for assessing the communication skills of infants and toddlers. American Journal of Speech-Language Pathology, 4, 47–59. DeCasper, A.J. & Spence, M.J. (1986). Prenatal maternal speech influences newborn’s perception of speech sounds. Infant Behavior and Development, 9, 133–150. Dunn, S.L., van Kleeck, A., & Rossetti, L.M. (1993). Current roles and continuing needs of Speech-Language Pathologists working in neonatal intensive care units. American Journal of Speech-Language Pathology, 2, 52–64. Jusczyk, P. (1995). Infants detection of the sound patterns of words in fluent speech. Cognitive Psychology, 29, 1–23. Oller, D. (1994). Speech-like vocalizations in infancy: An evaluation of potential risk factors. Journal of Child Language, 21, 33–58. Werker, J., Lloyd, V.L., Pegg, J.E., & Polka, L. (1996). Putting the baby in the bootstraps: Towards a more complete understanding of the role of input in infant speech processing. In J.L. Morgan & K. Demuth (Eds.), Signal to syntax. (pp. 427–447). Mahwah, NJ: Lawrence Erlbaum.