Proficiency in a second language influences processing of print-to-sound mappings

A hallmark of word naming in deep orthographies, effects of spelling-sound regularity and consistency are considered to reach stability in adulthood. We investigated whether these effects were modulated by second language (L2) proficiency in native English and native Spanish speakers. Participants named English, Spanish and language-ambiguous words, but only the English words were used in the analysis. Participants in each group named English words with irregular-inconsistent mappings (e.g., PINT) more slowly and less accurately than words with regular-consistent mappings (e.g., GATE). Higher English proficiency reduced the magnitude of the regularity-consistency effect in both groups. Critically, native English speakers revealed a U-shaped relationship between L2-Spanish proficiency and the regularity-consistency effect on naming latencies. The current findings add to a growing body of literature that considers the boundaries within which L2 proficiency can influence native language (L1) performance. Results suggest that L2 proficiency may destabilize a fundamental aspect of L1 literacy, the computation of phonology from text, which is known as a highly stable psycholinguistic effect. This suggests that the language system is dynamic, remaining plastic in early adulthood.