Morphological and phonological units in the Arabic mental lexicon: Implications for theories of morphology and lexical processing

This dissertation investigates the cognitive relevance of selected morphological and phonological units in the Arabic mental lexicon. The morphological units are sound and weak roots, etymons, phonetic matrices, and sound and weak patterns. The phonological units are vowels and consonants. The work is motivated by a controversy in Arabic morphology that is paralleled by a cross-linguistic debate in lexical processing. There are two views in Arabic morphology, the stem-based theory and the morpheme-based theory that is represented by two sub-theories. The first sub-theory argues that derivations are based on roots and patterns and the second proposes that the root should be replaced by the etymon and the phonetic matrix. The morpheme-based theory is congruent with lexical processing hypotheses that propose that complex words are accessed and represented as morphemes. The stem-based theory maintains that derivation is stem or word-based and is in line with the whole word hypothesis of lexical processing. These theoretical positions on Arabic morphology and lexical processing were tested in six priming experiments. One objective of these experiments was to test which of these morphemes prime word recognition. Another objective was to test the prediction of connectionism, another lexical processing hypothesis, that priming time correlates with prime-target overlap. A third objective was to examine how abstract the processing of these morphemes could be. The cognitive status of vowels and consonants was tested using a letter-circling task. The results of the online studies have shown that both roots and etymons facilitate word recognition significantly more than orthographic controls. However, non-ordered etymons, phonetic matrices, and patterns did not facilitate word recognition. Weak roots had priming effects only when primes and targets shared a vague semantic relationship. There was no correlation between priming time and meaning and/or form overlap. The lack of priming with non-ordered etymons suggests that there could be limits on abstractness in lexical processing. The results of the offline task suggest that root consonants are more salient than other letters. On the whole, the results support a morpheme-based theory of Arabic morphology and a localist view of lexical processing that assumes a morphemic stage in word recognition