The ability to speak a second language isn’t the only thing that distinguishes bilingual people from their monolingual counterparts—their brains work differently, too. Research has shown, for instance, that children who know two languages more easily solve problems that involve misleading cues. A new study published in Psychological Science reveals that knowledge of a second language—even one learned in adolescence—affects how people read in their native tongue. The findings suggest that after learning a second language, people never look at words the same way again.

Eva Van Assche, a bilingual psychologist at the Univer­sity of Ghent in Belgium, and her colleagues recruited 45 native Dutch-speaking students from their university who had learned English at age 14 or 15. The researchers asked the participants to read a collection of Dutch sentences, some of which included cognates—words that look similar and have equivalent meanings in both lan­guages (such as “sport,” which means the same thing in both Dutch and English). They also read other sen­tences containing only noncognate words in Dutch.

Van Assche and her colleagues recorded the participants’ eye move­ments as they read. They found that the subjects spent, on average, eight fewer milliseconds gazing at cognate words than control words, which suggests that their brains processed the dual-language words more quickly than words found only in their native language.

“The most important implication of the study is that even when a per­son is reading in his or her native language, there is an influence of knowledge of the nondominant second language,” Van Assche notes. “Becoming a bilingual changes one of people’s most automatic skills.” She plans to investigate next whether people who are bilingual also process auditory language information differently. “Many questions remain,” she says.

Note: This story was originally printed with the title "Bilingual Brains"