Research on working memory and language has followed two quite divergent paths. The first line of inquiry examines questions relating to the components and organization of working memory – whether there are specialized buffers, the nature of the link to long-term memory, and so on. For the most part, studies of this type have little to say about the workings of language per se – why it has the particular types of relative clauses or patterns of verbal agreement that it does, for example. These issues fall under the purview of a different line of research, which seeks to trace various fundamental properties of language to the cognitive processes involved in the storage and manipulation of information – working memory, broadly construed. The goal of the latter research program, which I will try to advance here, is to establish that general properties of working memory, however they are ultimately integrated into a theoretical model, can contribute to a deeper understanding of the human language faculty. I will focus here on three phenomena that help illustrate this point – a restriction on the interpretation of reflexive pronouns, a curious prohibition on phonological contraction in a type of wh question, and a baffling constraint commonly known as the ‘that-trace effect.’ A careful examination of their properties reveals a previously unsuspected finding: they are shaped by the need to minimize processing cost, a key factor in our understanding of working memory as well.

This chapter outlines an emergentist approach to understanding why human languages have the particular properties that they do and how those properties are acquired by children. Drawing on a variety of examples, it illustrates the role of two factors in shaping language and its acquisition: limitations on the resources available for processing utterances in real time, and the role of input in facilitating the acquisition of particular words and patterns. Both these factors fit well with a key claim of linguistic emergentism, which is that the human language faculty is shaped by forces – cognition, perception, memory, computation, and experience – that are not themselves linguistic in character. The emergentist approach thus provides an alternative to theories that attribute the unique human ability to learn and use language to an inborn Universal Grammar. The second line of inquiry pursued investigates the emergence of particular features of Korean, especially reflexive pronouns and relative clauses, in child and adult heritage learners. The developmental profile associated with these phenomena fits well with the emergentist approach to language, and helps confirm that heritage languages are learned in essentially the same way as languages that are acquired in a monolingual setting.