Morphology In linguistics, morphology is commonly described as the study of words, their internal structure, and their formation. While this subdiscipline of grammar may have been studied by the first linguists in the history, the term morphology came into use only centuries after the terms for other subdisciplines as phonology or syntax (Haspelmath and Sims, 2013). The term morphology was originally coined by Johann Wolfgang von Goethe for biology to refer to the study of the forms of living organisms (Aronoff and Fudeman, 2010). In linguistics, morphologists are interested in how complex words are formed by grammatical rules from the primitive elements: morphemes.
Complex word A word is made up of a sequence of sounds from a certain language. Some sounds may be broken down into phonological features (e.g., [± voice], [± nasal]), while others may instead contain syntacticosemantic (henceforth, synsem) features, i.e., grammatical or functional meanings, as their basic representations. For instance, the final /t/ sound in words such as waste, act, adopt, etc. can be distinguished from the final /t/ in words such as passed, lacked, or stopped. The final /t/ in the latter set of words is a morpheme that is composed of the synsem feature [+past], to denote past tense. On the other hand, leaving out the /t/ sound in the first set of words (*[weIs], *[æk], *[@"dæp]) does not result in non-past tense meaning for those words. Moreover, synsem features can be realized phonologically differently by their phonological or morphological contexts. For instance, the feature [+past] surfaces as /d/ after words ending in non-t/d voiced consonants, e.g. joined or bored, in default cases. In this dissertation, complex words refer to multimorphemic words. It is important to note that this is not the same as being
featurally complex (Embick, 2015). For example, the English words I or we contain both a first person feature [+1] and a number feature [±pl]. Yet they are not complex words by the definition in this dissertation. By contrast, words such as bent, left, or bit are complex as they are composed of more than one morpheme: their core basic meaning and the synsem feature [+past].
The morpheme as a syntactic object The previous description indicates that I as- sume morphemes to be discrete pieces that inevitably involve the mapping between sound and meaning. In this dissertation, I follow (Embick, 2015) in treating morphemes as the primitive units for syntactic operations, using the Distributed Morphology (henceforth, DM) framework. Accordingly, I also assume two types of morphemes in the grammar: functional morphemes and Roots. Functional morphemes possess closed-class synsem features (e.g., [±past] or [±pl]) and have no phonological features, while Roots (e.g.,√House or
√
Sleep) make up the open-class vocabulary and they do not contain synsem features but do have underlying phonological representations. In the psycholinguistic literature, the term stem is generally used, as a less technical notion of the term Root, to refer to the remaining mor- pheme after the removal of all functional morphemes in a word (Goodwin Davies, 2018). As seen earlier, the same morphemes can surface differently as conditioned by their phonolog- ical or morphological contexts (e.g., the plural morpheme in English can surface as /s/ as in cats or /z/ as in dogs). These conditioned variants of morphemes are referred to as allo- morphs. Within the DM framework, words are not architecturally different from phrases. It is the morphemes that are the theoretical primitive object to be syntactically operated on. Thus, it is not essential to define the notion of word theoretically. This dissertation assumes the informal, non-technical use of the term word, which are more in accordance with what language users are familiar with, rather than a theoretical object.
Complex word formation Morphology is traditionally divided into inflectional mor- phology and derivational morphology. Inflection generally relates different forms of the same word without creating a new lexical meaning nor forming a new lexical category (e.g., noun, verb). For instance, classes and classed are inflected forms of class. Inflection
often includes features such as tense, number, gender, person, case, etc. On the other hand, derivation generally forms new words, thus creating new lexical meanings and sometimes forming new lexical categories. For example, classify, classy, classic, classical are derived from class. Inflection and derivation share similar means of formation such as affixation: suffixes (e.g., touch-es, touch-able), prefixes (e.g., re-touch), etc. Another common morpho- logical process apart from inflections and derivations is compounding. While like derivation, compounding also forms a new word, the formation process typically involves two or more free lexical elements, e.g., blackboard, football, wallpaper, without, etc. However, the distinction between derivation and compounding is not always clear-cut. A fuzzy boundary between the two processes arise in the cases of elements that are bound, i.e., not being able to appear freely without attaching to other elements (e.g., vis- in visible), but also carry a robust lexical meaning, e.g., derm in dermatology. Moreover, compounds may undergo diachronic change, being subject to altered phonological, structural, and semantic behaviors (Bauer et al., 2013; Lieber, 2017; Trips, 2013). Over time, their free elements may them- selves become affixes, with an unclear timeline for the completion of the transition (Bauer, 2005; Lieber, 2017) (see Bauer et al., 2013; Lieber, 2017; Lieber and ˇStekauer, 2011; Olsen, 2014; Ralli, 2010 for more discussion).
Under the DM framework, there is no theoretical distinction between inflectional and derivational morphology because both inflectional and derivational morphemes are syntactic terminals that are similarly operated on (Embick, 2015, pp. 47). Derivational morphemes in DM function as a categorizer for the Roots. Roots are always combined with their categorizer to denote their lexical category. Their categorical defining heads can either be derivational morphemes (e.g., n, v, a: noun, verb, adjective) or null. Compounding in DM, on the other hand, is “a word-sized unit containing two or more Roots” (Harley, 2011, pp. 130).
Lexical processing Lexical processing refers to the retrieval of a representation of lexical entries from the mental lexicon. The process is done through the matching between a sensory representation of a stimulus and its representation stored in the mental lexicon.
Lexical access does not refer to the actual processing but to the final outcome where the meaning is accessed (Taft, 2001). A key topic in lexical processing concerns the processing of morphologically complex words. Different models of morphological processing have been proposed regarding what should be stored in the lexicon and how it is retrieved. (see Section 2.3.1 for details.)