Communication skills of twins and higher multiple birth children : implications for speech and language acquisition

Abstract

A number of theoretical approaches have been proposed to account for the acquisition of speech and language in children. One way in which these approaches differ concerns the relative importance attributed to innate learning mechanisms versus environmental factors for the acquisition of communication skills. The research reported in this thesis aimed to add to the knowledge base of how speech and language is acquired in the preschool years by investigating language learning environments other than those involving singleton children. To this end, the syntactic, semantic, pragmatic, articulation and phonological skills of twins, triplets and quintuplets were described. In order to establish distinct communication profiles for the multiple birth children, comparisons were made between matched singletons and normative data; between children within a multiple birth set; as well as comparing communications skills of these children when they are interacting with different conversational partners. The differences between multiple birth children and singletons that were identified were assessed in terms of the duration of their presence and whether the differences were delays, disorders or alternative developmental paths. Investigations were then conducted to identify some of the possible pre- and post-natal influences on the communication development of same age siblings sharing the same language learning environment. From a clinical perspective, the investigation also aimed to further address the need for, and efficacy of, intervention with multiple birth children. The results of the studies indicated that the communication profiles of multiple birth children not only varied from those of singletons, but also differed according to the number of same aged siblings within a set. While siblings within sets did not have identical communication profiles, similarities were found. Of the communication skills assessed, phonological development showed the most variation between twins and higher multiple birth children. Twins were prone to phonological disorder while the other multiple birth children evidenced primarily delayed phonological development. The twins phonological difficulties were shown to persist beyond the preschool years suggesting that their acquisition of literacy may be at risk and that, consequently, intervention is warranted.