In recent years, it has been suggested that social robots have potential as tutors and educators for both children and adults. While robots have been shown to be effective in teaching knowledge and skill-based topics, we wish to explore how social robots can be used to tutor a second language to young children. As language learning relies on situated, grounded and social learning, in which interaction and repeated practice are central, social robots hold promise as educational tools for supporting second language learning. This paper surveys the developmental psychology of second language learning and suggests an agenda to study how core concepts of second language learning can be taught by a social robot. It suggests guidelines for designing robot tutors based on observations of second language learning in human–human scenarios, various technical aspects and early studies regarding the effectiveness of social robots as second language tutors.

In this article, we review research on child–robot interaction (CRI) to discuss how social robots can be used to scaffold language learning in young children. First we provide reasons why robots can be useful for teaching first and second languages to children. Then we review studies on CRI that used robots to help children learn vocabulary and produce language. The studies vary in first and second languages and demographics of the learners (typically developing children and children with hearing and communication impairments). We conclude that, although social robots are useful for teaching language to children, evidence suggests that robots are not as effective as human teachers. However, this conclusion is not definitive because robots that tutor students in language have not been evaluated rigorously and technology is advancing rapidly. We suggest that CRI offers an opportunity for research and list possible directions for that work.

We present a large-scale study of a series of seven lessons designed to help young children learn English vocabulary as a foreign language using a social robot. The experiment was designed to investigate 1) the effectiveness of a social robot teaching children new words over the course of multiple interactions (supported by a tablet), 2) the added benefit of a robot's iconic gestures on word learning and retention, and 3) the effect of learning from a robot tutor accompanied by a tablet versus learning from a tablet application alone. For reasons of transparency, the research questions, hypotheses and methods were preregistered. With a sample size of 194 children, our study was statistically well-powered. Our findings demonstrate that children are able to acquire and retain English vocabulary words taught by a robot tutor to a similar extent as when they are taught by a tablet application. In addition, we found no beneficial effect of a robot's iconic gestures on learning gains.

Relational terms (e.g., verbs and prepositions) are the cornerstone of language development, bringing together two distinct fields: linguistic theory and infants' event processing. To acquire relational terms such as run, walk, in, and on, infants must first perceive and conceptualize components of dynamic events such as containment–support, path–manner, source–goal, and figure–ground. Infants must then uncover how the particular language they are learning encodes these constructs. This review addresses the interaction of language learning with infants' conceptualization of these nonlinguistic spatial event components. We present the thesis that infants start with language-general nonlinguistic constructs that are gradually refined and tuned to the requirements of their native language. In effect, infants are trading spaces, maintaining their sensitivity to some relational distinctions while dampening other distinctions, depending on how their native language expresses these constructs.

How might syntactic bootstrapping apply in Turkish, which employs inflectional morphology to indicate grammatical relations and allows argument ellipsis? We investigated whether Turkish speakers interpret constructions differently depending on the number of NPs in the sentence, the presence of accusative case marking and the causative morpheme. Data were collected from 60 child speakers and 16 adults. In an adaptation of Naigles, Gleitman & Gleitman (1993), the participants acted out sentences (6 transitive and 6 intransitive verbs in four different frames). The enactments were coded for causativity. Causative enactments increased in two-argument frames and decreased in one-argument frames, albeit to a lesser extent than previously found in English. This effect was generally stronger in children than in adults. Causative enactments increased when the accusative case marker was present. The causative morpheme yielded no increase in causative enactments. These findings highlight roles for morphological and syntactic cues in verb learning by Turkish children.