This chapter discusses how the Cognition Hypothesis can be applied in the study of L2 speech production. The paper presents a bilingual model of speech production, which also incorporates psycholinguistic processes involved in dialogic interactions, and discusses how attention is allocated in producing L1 and L2 speech. It is then argued that the Cognition Hypothesis can be supported by theoretical considerations and empirical findings from the psycholinguistic study of speech production. The chapter shows how tasks increasing in complexity along the resource-directing dimension can enhance second language learning through the extension of the L2 conceptual system, which in turn triggers lexical, syntactic and morphological development by driving learners to make new form-meaning connections and by providing practice opportunities.