We explore the predictors of early mastery versus error in children’s acquisition of American Sign Language. We hypothesize that the most frequent values for a particular parameter in prelinguistic gesture will be the most frequent in early signs and the most likely sources of substitution when signing children make errors. Analyses of data from a longitudinal study of the prelinguistic gestures of five Deaf and five hearing children and a longitudinal study of four Deaf children’s early signs have revealed evidence of significant commonalities between prelinguistic gesture and early sign. This apparent continuity between prelinguistic gesture and early sign reflects constraints operating on the infant—in all likelihood, motoric constraints—that seem to persist into the first-word period in both major language modalities. In sign, as in speech, the production of first signs uses building blocks that are available to the prelinguistic child.*
1. Patterns in the acquisition of child phonology
What are the predictors of early mastery versus early error in child phonology? Can we predict which articulatory features will be successfully rendered by young children when they attempt words or signs? And what factors determine the form of their errors, particularly their substitution patterns? The literature on the acquisition of speech suggests that children in the early word-period will be successful in producing phonetic segments that were frequent in their earlier (and sometimes concurrent) babbling (Locke 1983, MacNeilage et al. 1997).
In this article, we explore a sizable corpus of early signs produced on videotape by four Deaf children of Deaf parents; their ages ranged from 5 to 17 months over the course of the study.1 These children were acquiring American Sign Language (ASL) as their first language. To develop predictions about which formational aspects of signs would be successfully produced by these children, we turned to data on prelinguistic gestures produced by two other groups of children. We use the term prelinguistic gesture to refer to the set of nonlinguistic gestures that are produced prior to the onset of language production and/or concurrently with early words or signs. Prelinguistic gestures were identified in longitudinally collected videotapes from five hearing children with no sign exposure and five Deaf children of Deaf signing parents. The ages of the infants who contributed prelinguistic gesture data ranged from 7 to 13 months.
We test two broad hypotheses: (1) on any parameter of sign formation, the most frequent values in prelinguistic gesture will also be the most frequent in early signs; and (2) on any parameter of sign formation, the most frequent values in prelinguistic gesture will be the most likely sources of substitution when young signing children make errors. The fact that we have data on prelinguistic gestures from Deaf infants reared in signing families and from hearing infants with no sign exposure will give us insight into the source of any articulatory preferences that appear in prelinguistic gesture and in early signing. Articulatory preferences that are identified in the prelinguistic [End Page 292] gesture and early signing of Deaf infants may reflect children’s early experience with ASL. In contrast, articulatory preferences that are identified in early signing, in the prelinguistic gesture of Deaf infants, and also in the prelinguistic gesture of hearing infants are likely to reflect the motoric constraints to which all developing children are subject. Studies such as Conlin et al. 2000 and Meier et al. 1998 have found evidence that important patterns in early sign development are consistent with independently attested trends in infant motor development. We will show that with respect to most, but not all, parameters of sign formation, there is a smooth transition between prelinguistic gesture and early sign (see also Petitto & Marentette 1991). We will rely on explanations that are largely founded in infant motor development to account for our results.