Twin–singleton language differences.

Abstract

Differences on 13 child language variables were investigated for 12 sels of 24-ycar-old twins and 24 singletons, matched lor age and socioeconomic stains. Two-hour spontaneous speech records were obtained in the home. A regression analysis assessed the contribution of the biological (perinatal) and maternal speech variables to the child language measures. Rate of mother's speech to child was the most important predictor of child language performance. Singletons talked more, addressed more utterances to iheir mothers, and combined phrases into sentence (subject + verb) form to a greater extent than did the twins. Environmental factors appear to be influential in encouraging use of verbal expression beyond acquisition of phrase competence. Biological factors make a smaller contribution.Most measures of twin language and intellectual development show twins progressing at a slower rate than singletons (Day, 1932;Koch, 1966;Mittler, 1971;Breland. 1974). Some of the difference may be due to the biological effects of twin pregnancies and births, which may entail competition for space and nutrition in utero and always result in lowered birthweight (McKeown & Record, 1952;Naeye, 1964; Babson & Bramhall, 1969;Howard & Brown, 1970; Wilson, Note 1). However, some of the difference in language may also be due to the parental environment, and particularly parental verbal stimulation, which twins, as opposed to singletons, have to share (for the importance of linguistic environment cf. Cross, 1977;Snow, 1972 Snow, , 1977 Seitz& Stewart, 1975; Whitehurst, Note 2). Record, McKeown and Edwards (1970) found that twins whose partners had died before one month of age had average verbal reasoning quotients at age 11, whereas the verbal reasoning scores of full twin sets were below average. They concluded from this and from their negative findings regarding birth factors that lower verbal intelligence in twins was not due to prenatal or perinatal handicapping conditions, but to post-natal and environmental experiences.None of these authors, however, examined directly the way in which twins differ from singletons in their day-to-day experiences in the home. Lytton, Conway, and Sauve (1977) did just this, and obtained first-hand records of twins', singletons', and their respective parents' speech in a global way. The study reported here examined the structure and complexity of twins', singletons', and their respective mothers' speech in detail, Requests for reprints should be sent to

Genetic Effects on Children’s Conversational Language Use

“…Of interest, this finding calls into question the common notion that twins tend to have less advanced language skills compared with singletons. Perhaps reported delays are most pronounced at younger ages (Conway et al, 1980;Hay et al, 1987;Rutter et al, 2003). The third form of evidence supporting the validity of the language sample measures is the consistent mean differences favoring children without a history of expressive language difficulties compared with those who have a reported history of expressive difficulties.…”

Factors affecting the appearance of ‘twin language’: An original language naturally developing within twin pairs

“…It has generally been believed that the language development of twins is delayed in comparison with that of singletons because of their low birth weight and postnatal language learning environment -immaturity of physical development and reduced individual conversation with their mother (1)(2)(3)(4)(5)(6)(7)(8). However, a recent study suggested that 'twin language' affects their delay of normal language development (9).…”

Children’s History of Speech-Language Difficulties: Genetic Influences and Associations With Reading-Related Measures

“…In the present study, the prevalence of persisting difficulties was 16% for articulation, 12% for expressive language, and 3% for receptive language. Consequently, in comparison to the singleton literature, rates of speech-language difficulties in the present twin sample appeared somewhat higher.Higher rates of speech-language difficulties in twins are likely due to higher rates of the same risk factors that contribute to speech-language difficulties in singletons, specifically biological factors, such as prematurity, lower birth weight, and so forth (Field, Dempsey, & Shuman, 1981;Luke & Keith, 1992), and social factors, such as less individualized parental interaction (e.g., Conway, Lytton, & Pysh, 1980;Thorpe, Rutter, & Greenwood, 2003). In part because of these risk factors, twins often receive more frequent professional vigilance, which may in turn make communication difficulties more likely to be identified than in singleton children.…”