This presentation engages the issue of linguistic proximity and distance in the context of heritage Arabic. We investigate proximity and distance both in the traditional typological sense (having a shared linguistic family) and in the theoretical sense (sharing linguistic features that govern the formation of linguistic forms at the lexical, phrasal, and sentential levels). We focus particularly on word formation and the notion of root as a basic building block for words, the representation of sentential negation and its interaction with lexical categories, and question formation, with special focus on wh-in-situ vs. wh-movement as competing options with markedly different statuses in the linguistic space where the heritage language is acquired and spoken.  We explore the implications of our findings for the debate about the acquisition and maintenance of closely related languages and how that debate could be further sharpened by closer examination of the notions of linguistic proximity and distance.