This paper investigates the morpheme-specific phonological behavior of the Moroccan Arabic definite article [l-] and its variable assimilation process with nouns that begin with the palatal fricative [ʒ]. By analyzing of a corpus of these nouns, I identify one major factor that influences this variability: the context following [ʒ]. The results of a nonce word experiment I conducted show that speakers follow the lexical tendencies when generalizing to [ʒ]-initial nonce words,which does not align with the assumptions proposed in the literature (Harrell, 1962; Heath, 1987, 1989; Freeman, 2016). I will show that a Maximum Entropy (Goldwater and Johnson, 2003) model together with Lexically-indexed Constraints (Pater, 2000, 2009) successfully accounts for both the categorical behavior of known [ʒ]-initial words as well as the variability predicted for nonce words. Proceedings of the Annual Meetings on Phonology, 1(1)