Vowel unpredictability in Hijazi Arabic monosyllabic verbs

We study the distribution of vowels in the monosyllabic verbs of Urban Hijazi Arabic, showing that speakers use the presence of a root emphatic consonant to partially predict the quality of stem vowels. The effect of the emphatic is observed in the lexicon, and is productively extended to nonce verbs, showing that speakers generalize over lexical representations that include both vowels and consonants; the purely consonantal representations that are commonly assumed for Arabic are insufficient to capture speakers' knowledge of consonant-vowel interactions. We propose a probabilistic analysis that learns lexical trends from surface forms and extends them productively to nonce words.