From the journal Language Problems and Language Planning:
"Previous work has examined the potential of Esperanto as a pedagogical tool in classroom foreign language learning in England, where limited language input of sometimes as little as one hour per week is the norm. The work reviewed here focuses on child learners aged 6 to 12 and was carried out between 2006 and 2016. Two Esperanto-based language awareness programmes have provided primarily descriptive insights, suggesting that learning Esperanto may result in greater metalinguistic awareness and more positive attitudes to other languages and cultures. However, the language awareness programmes were implemented without matched comparison groups and therefore could not reveal whether the learning of Esperanto would lead to different results than the learning of other languages. Classroom-based research that included matched comparison groups has sought to address this issue. Specifically, three studies investigated the questions of whether learning Esperanto as opposed to learning other languages would help enhance children’s metalinguistic awareness and thus contribute in turn to more successful learning in a limited-input classroom context. On the one hand, results indicate that for novice child learners, Esperanto was easier to learn than French, and that learning Esperanto may have a levelling effect that compensates for individual differences between children. On the other hand, the findings also show that these apparent advantages of Esperanto did not translate into measurably greater benefits for the development of metalinguistic awareness, or greater subsequent success in learning another foreign language. Moreover, learning Esperanto could not compensate for low language learning aptitude. In view of these sobering results, a number of proposals are made on how to take forward the research agenda. These proposals include further research into the potential benefits of using form-focused instruction (based on any language) with children as well as the effects of learning Esperanto in novice adult learners."