Productivity and priming: Morphemic decomposition in Arabic

Word formation in Arabic involves the interleaving of two abstract morphemes-a root consisting exclusively of consonants and conveying semantic meaning, and a word pattern comprised primarily of vowels and conveying phonological and morpho-syntactic information. In masked and cross-modal priming experiments, we probed the processing relationship between these two morphemes during word recognition by examining the roles of word pattern and root productivity (family size) in producing word pattern priming in Arabic deverbal nouns. Co-varying word pattern and root productivity in a 2 × 2 design, we found that priming was determined entirely by the productivity of the root. Even very productive word patterns did not prime if they appeared in the context of an unproductive root. This pattern of results, which is identical in cross-modal and masked priming, indicates the importance of the root in driving the on-line decomposition of Arabic surface forms into their constituent morphemes.