Decomposability and the Effects of Morpheme Frequency in Lexical Access

Abstract

This dissertation addresses an unanswered question in Arabic psycholinguistics. Arabic words are characterized by their nonconcatenative structure, in which a consonantal root that encodes the main semantic content is interleaved with a derivational pattern (called "binyan", pl. "binyanim"), which is typically vocalic but may also contain consonantal elements and contributes grammatical information. The canonical example of the Semitic root and binyan system is the combination of root /ktb/ which denotes the broad semantic sense of "writing" with verbal binyan /CaCaC/ (with Cindicating a root consonant) to form [katab] "he wrote" and with nominal place binyan/maCCaC/ to form [maktab] "office". Although significant work has been done on the psycholinguistic reality of Arabic morphemes by exploring various phonological, morphological and semantic features across numerous experimental modalities in both the visual and auditory domains (Boudelaa and Marslen-Wilson, 2004, 2005, 2011), no study has investigated the roles of base/morpheme frequency and surface/word frequency and their implications for underlying morphological structure in the lexicon of Arabic as has been done for English, Dutch, and Finnish (Baayen et al., 1997; Alegre and Gordon, 1999; New et al., 2004; Taft, 1979, 2004). Competing models of word recognition propose various integrations of morphology. Whole-word models suggest that there are no separate representations for morphemes, and that the co-activation of related words can be attributed to similarity in form and meaning (Norris and McQueen, 2008; Tyler et al., 1988). Decomposition models posit that words are recognized by accessing the words' constituent morphemes (Meunierand Segui, 1999; Taft et al., 1986; Wurm, 2000). Hybrid models incorporate multiple pathways to recognition. Words are either recognized holistically or by their constituent morphemes depending on multiple factors (Balling and Baayen, 2008; Taftand Nguyen-Hoan, 2010; Lopez-Villasenor, 2012). Of most relevance to the current study is the role of the productivity of the words' derivational affixes: words with unproductive affixes are processed holistically whereas words with productive affixes are processed as a function of their morphemes. This dissertation presents results from four auditory lexical decision experiments performed with native Jordanian speakers in Amman, Jordan, and provides evidence that binyan productivity determines whether the frequency of the base morpheme affects the speed of recognition. By manipulating root and word frequency for three binyanim, one more productive and two less productive, I provide evidence that verbs in the productive binyan are fully decomposable during lexical access and verbs in less productive binyanim are recognized holistically. For a more productive binyan, I examine Binyan I of the form /CaCaC/, and two less productive binyanim are Binyan VIII of the form /iCtaCaC/and Binyan X of the form /staCCaC/. These results together support a hybrid model of lexical access in which some words are recognized via decomposition into the morphemes they are composed of, and others are recognized by their whole word form. These results are consistent with those of Balling and Baayen (2008); Taft and Nguyen-Hoan (2010); Bertramet al. (2000), among others, as derivational affix productivity is the deciding factor determining whether a word will be recognized holistically or decomposed during lexical access.