WEDNESDAY, Aug. 26, 2009 (HealthDay News) -- Bilingual people are unable to completely switch off their second language, even when reading in their native language, new research suggests.
Researchers from Ghent University in Belgium had 45 college students who spoke Dutch as their native language and English as a second language read several sentences written in Dutch.
The sentences contained cognates, which are words that originate from the same ancient language and have retained a similar meaning and form across languages. The English word "cold" and the German word "kalt" -- both derived from Middle English -- are cognates.
While reading the sentences, the researchers recorded at what points the students' eye movements paused. This is called a "fixation location," the study authors explained in a news release from the Association for Psychological Science.
The study found the bilingual students spent less time looking at the cognates compared to the ordinary Dutch words, suggesting that there are overlaps in the brain's processing of the two languages that speed up cognate comprehension.
For example, the researchers found that in the sentence "Ben heeft een oude oven/lade gevonden tussen de rommel op zolder" ("Ben found an old oven/drawer among the rubbish in the attic"), the bilingual students read "oven" more quickly than "lade."
Even though participants did not need to tap into their second language to read their native language, the study suggests the second language is always active, and that being bilingual impacts processing of the native tongue, too.
The study was published in the August issue of Psychological Science.
The Society for Neuroscience has more on the bilingual brain.