For bilinguals, the use and knowledge of one language affects how they process the other. Various cross-linguistic influences (CLI) can be observed in both language production and comprehension across all domains of linguistics. We start by broadly exploring the concept of transfer, both negative and positive, and forward and reverse. In doing so, we identify various classifications of CLI. Following this, we review key studies on phonological, lexical, morphological, and syntactic transfer along with other types such as discursive, pragmatic, and sociolinguistic. We find that there are a number of factors that can determine the degree to which transfer emerges or whether it happens at all. We then review studies investigating the ability to switch between the two language systems. In doing so, we look at theoretical models that explain what facilitates language switching and what empirical studies tell us about the neural and electrophysiological activity that arises in language switching. Finally, we discuss dreaming and bilingualism and argue that dreaming in an L2, contrary to popular belief, does not necessarily imply fluency in that language.

In Chapter 10, we examine how cross-cultural pragmatics – in particular, cross-cultural research on expressions – can be applied to applied linguistics. More specifically, we explore how the study of expressions can provide insight into in-depth problems in language learning and language use, by examining cross-cultural pragmatic differences between the ways in which British learners of Chinese and Chinese learners of English evaluate a set of pragmatically important expressions in their target language. Chapter 10 reveals that the use of seemingly ‘simple’ pragmatically salient expressions such as sorry in English can cause significant difficulties for foreign language learners. In methodological terms, the present chapter first conducts an ancillary research, i.e. questionnaires, followed by a contrastive pragmatic exploration, i.e. interviews conducted with language learners.