Human language stands out among communication systems both for its level of abstractness and its level of complexity. Its complexity has led to theories of acquisition and processing that give language a special status, as an aspect of cognition that is largely innate (rather than acquired via general learning mechanisms), and largely encapsulated from other aspects of cognition and behavior. The complexity of language has also forced psycholinguists to cut language into more approachable subdomains of study, such as speech perception, word recognition, word production, sentence processing, etc. In this seminar, we will critically examine the arguments for treating language as a series of special systems. We will discuss several key subdomains of psycholinguistics, their relations to each other, and influences of non-linguistic aspects of cognition on language acquisition and processing.