Complex words have been the target of experimental research on word processing for the past 30–40 years. Studying polymorphemic words can contribute to a better understanding of the structure of the mental lexicon. There have been numerous studies on how morphologically complex and compound words are stored and accessed in different languages (Longtin et al., 2003 for French; Rastle et al., 2004 for English; Kazanina et al., 2008 for Russian; among others). However, very little has been done on less studied languages like Persian. The goal of the present study is to shed some light on the nature of the mental lexicon, and more specifically, on how compound verbs are represented and accessed. The study aims to assess the current theories of compound word processing in a less studied language (i.e., Persian) with a very productive compounding system.

This chapter is organized as follows. In Section 1.1, the mental lexicon will be defined followed by a description of the models and theories on lexical processing. In Section 1.2, the goal of the study will be explained, followed by the book outline in Section 1.3.

The Mental Lexicon

The mental lexicon encompasses ‘words,’ which are employed by the speakers of a language to represent the mappings between phonological forms that are used to refer to objects in the world and their corresponding meanings. Research on the mental lexicon has mainly concentrated on lexical processing and lexical representation.

To this end, scholars, who have tried to provide a definition of the mental lexicon, have found it quite challenging, since the boundaries of the subject as well as its contents are rather vague. Jarema and Libben (2007:2) have defined the mental lexicon as, “the cognitive system that constitutes the capacity for conscious and unconscious lexical activity.”

The mental lexicon has been examined and explained through studies on the structure of the lexicon and on the lexical processing and representation for several decades. Studies on the structure of the lexicon have attracted theoretical linguists, while studies on lexical processing and representation have enticed psycholinguists.

Models of the lexicon in theoretical linguistics can be considered as lying on a continuum. At one end are theories that consider the lexicon quite rich (Lexicalist Theories) and at the other, theories that consider the lexicon quite poor (e.g., Distributed Morphology).