abstract Reaction times for a translation recognition study are reported where novice to expert English–ASL bilinguals rejected English translation distractors for ASL signs that were related to the correct translations through phonology, semantics, or both form and meaning (diagrammatic iconicity). Imageability ratings of concepts impacted performance in all conditions; when imageability was high, participants showed interference for phonologically related distractors, and when imageability was low participants showed interference for semantically related distractors, regardless of proficiency. For diagrammatically related distractors high imageability caused interference in experts, but low imageability caused interference in novices. These patterns suggest that imageability and diagrammaticity interact with proficiency – experts process diagrammatic related distractors phonologically, but novices process them semantically. This implies that motivated signs are dependent on the entrenchment of language systematicity; rather than decreasing their impact on language processing as proficiency grows, they build on the original benefit conferred by iconic mappings.