<p>Skilled spelling of polysyllabic, polymorphemic words depends on constituent binding: the integration of orthographic, phonological, and morphological knowledge into stable lexical representations. The Lexical Quality Hypothesis predicts that when representations are fully consolidated, individual word properties lose independent predictive power, with item-level difficulty emerging only as interactions with individual differences in consolidation. Using feature-scored spelling accuracy in 111 college-aged adults modeled in a cross-classified mixed-effects framework, we tested this prediction directly. Frequency, rime consistency, schwa count, and morphological awareness produced null main effects, consistent with consolidated representations in a skilled adult sample. All three theoretically motivated interactions were significant: higher-vocabulary adults showed reduced frequency disadvantages and greater sensitivity to rime-level regularities, and adults with stronger prosodic awareness spelled schwa-containing words more accurately, indicating that suprasegmental sensitivity stabilizes orthographic representations when phonological surface forms are unreliable. These findings specify when statistical regularities suffice for spelling and when higher-order knowledge becomes necessary.</p>