Language mode theory proposes that language activation can span from a monolingual mode (predominant activation of one language) to bilingual mode (both languages activated). While some argue that linguistic performance is influenced by the language mode the bilingual speaker is in, others have found that language mode activation has no affect on performance. We show that changes in language mode can influence bilinguals’ language processing. Spanish–English bilinguals with both languages active (bilingual mode) took longer to reject non-words than Spanish–English bilinguals with one language active (monolingual English mode) and English monolinguals. In addition, reaction times for non-words were longer the more Spanish weighted the bilinguals were, with a linear relationship between non-word reaction times and bilingual dominance. Results can be best described by extending the Bilingual Model of Lexical Access of speech perception to reading.