Introduction: Identification of children with speech sound disorders is often assisted by acquisition norms, however, norms have predominantly been collected with monolingual children. Improved understanding of multilingual speech sound acquisition is required to facilitate identification of speech sound disorders, thought to be currently under referred in multilingual children in the UK.
Methods: A systematic literature review was conducted to investigate the impact of multilingualism on the acquisition of English speech sounds. Seven electronic databases were searched for scientific studies published between 1960 and 2010. Bibliographies were also searched and key authors contacted. Studies were included if i) the sample included individuals speaking more than one language, ii) one of the languages spoken was English, iii) the study investigated an aspect of phonetics or phonology, such as phoneme repertoires and phonological error patterns; (iv) participants were children (<18yrs). Studies were analysed thematically.
Results: Fifty one studies met the inclusion criteria. Most frequent language populations studied were Spanish-English, Cantonese-English and Pakistani-English. Twenty studies used an exploratory case study approach; 15 studies used an experimental design to investigate differences in typical and/or speech sound disordered bilingual and monolingual populations and 16 investigated bilingual populations and made comparisons to acquisition norms.
Conclusions: Patterns of bilingual speech sound acquisition can be atypical compared to those of monolingual children and influenced by interactions between grammatical structures and phonological characteristics of specific languages. Experimental studies were mixed in their findings, but tend to suggest that bilingual children are not disadvantaged in their acquisition of English speech sounds once language proficiency and amount of language exposure have been taken into consideration.
Findings are discussed in relation to the identification of multilingual children with speech sound disorders.