How Orthographic Transparency Shapes Word Learning and Retention in Monolingual and Bilingual Adults

The current study examined orthographic learning in monolingual English and bilingual Welsh-English adults using English-like and Welsh-like novel written words based on orthographic patterns. Participants completed an orthographic learning task with repeated learning cycles, followed by a novel word recognition task one or two days later. Monolingual and bilingual participants showed comparable learning rates of English-like words. Within bilinguals, learning was modulated by the orthographic characteristics of the novel words: English-like items were learned more rapidly than Welsh-like items, an effect that emerged in later learning cycles. Word recognition accuracy and d-prime performance were not modulated by orthographic transparency, though English-like words were recognised more quickly. We found no evidence that Welsh vocabulary knowledge or language exposure influenced learning accuracy or recognition, though higher Welsh vocabulary scores were unexpectedly associated with slower word recognition reaction times. These findings suggest that monolingual and bilingual adults learn English-like orthographic forms to a similar degree of efficiency, and that English-like forms are learned more efficiently than Welsh-like forms. We did not find evidence that subsequent recognition of learned written words is modulated by orthographic transparency. Thus, longer-term retention of orthographic word forms may depend on domain-general language mechanisms rather than language-specific orthotactics.