Approximately one in five primary school pupils in England are classified as having English as an
additional language (EAL), meaning that they routinely use, or are exposed to, languages other than English. It is commonly thought that EAL learners’ first languages (L1s) can be leveraged to positively impact their linguistic and academic development in English. However, despite an abundance of theoretical and observational evidence used to argue this position, there is little experimental evidence to clarify the extent and nature of any relevant causal relationships. This gap in evidence was revealed in the first original contribution of this thesis: a systematic review of experimental research on the educational effects of mediating primary and pre-primary multilingual learners’ learning through their L1.
An extensive search of twelve bibliographic databases revealed only ten studies that met the
review’s inclusion criteria. The pedagogical focuses of these studies varied, and the overall picture
was unclear. However, five studies coalesced around the use of L1 as a mediating tool for teaching
English vocabulary. Of these, three found that L1-mediation was associated with improved
knowledge of the target vocabulary, one found an advantage associated with not using the L1, and
the remaining study had mixed results. None of these studies were conducted with linguistically
diverse groups of students, typical in English schools.
The promising, if somewhat tentative, conclusion invited by the systematic review informed the
second original contribution of this thesis: a randomised crossover trial with linguistically diverse
students, comparing the effects of L1-mediated teaching and English-only teaching on English
vocabulary learning. Forty EAL learners aged from 8 to 11 years, representing 14 different L1s took part. Participants watched short videos that explained the meanings of items of vocabulary taken from the National Curriculum for England. The spoken content of the videos was either in each participant’s L1 or in English. Analysis of the expressive and receptive knowledge of the target words following each condition revealed no statistically significant differences in outcomes.
The implications for pedagogy and future research are discussed, especially the imperative to
conduct more and better research to add clarity to our understanding of the causal relationships
between different types of L1-mediation and linguistic and academic success in linguistically diverse classrooms