A Critical Meta-analytic Exploration of Birth Order Effect on L1 Onset Time of Speaking and Language Development Progression; Is the Pointer towards First or Later Borns?

Abstract

Among the various underlying issues behind First Language (L1) acquisition processes, child Birth Order (BO) effect is one of the recent revitalized enquires of research of the 1900s but is confounding with many contradictory results in the literature. In this research, the intention was to elucidate if first-born or later-born children typically outperform in their language development processes. To this end, a systematic meta-analytic examination of child BO from 1970 to 2014 was undertaken in major related databases including TIRF, CHILDES, John Wiley, Taylor & Francis, PubMed and Science Direct. Studies in which language development had been mapped on BO effect and published from 1970 were included and the rest excluded from initial data collection. Finally, the research outcomes in which BO effects had been claimed to have caused delayed language development among either of the groups mentioned above have been discussed critically to explicate the existing contradictory findings.