An Overview of Conceptual Models and Theories of Lexical Representation in the Mental Lexicon

Since the crucial importance of vocabulary knowledge in the language learning process has finally been recognized, the mental lexicon has also been the focus of attention in a number of theoretical and empirical research papers and books. Aitchison (2003) claimed that there are two fundamental reasons that justify the need for the mental lexicon to be organized. On the one hand, the sheer number of words call for logical ordering because, as she reasons, psychologists have indicated that human memory is “flexible and extendable” as long as “the information is structured” (p. 5). The other reason for the organization of the mental lexicon is the impossible speed with which words can be found and recalled from tens (or maybe hundreds) of thousands of words. Valuable sources of empirical evidence have been provided by word searches and slips of the tongue, aphasic research and psycholinguistic experiments. The findings of theoretical research have also contributed to our understanding of the lexical processes in the mind (Aitchison, 2003). Therefore, the aim of the chapter is to give an up-to-date overview of the theories and models of the first language mental lexicon, followed by a similar analysis of the bilingual lexicon. Following the definition of key concepts, an argument is developed for a view of vocabulary knowledge that encompasses both mental representations encoded in memory as well as ability and control in the usage of this knowledge in producing and comprehending language. The chapter points out that while the mental lexicon might not have a specific modular localization in the human brain, it can serve as a useful metaphor in modeling and understanding how words are stored, organized and accessed in the different languages one speaks.