Bilinguals have the remarkable ability to switch from one language to the other. In a new study, Jason Gullifer and colleagues from Pennsylvania State University, USA, looked at whether language switching incurs a processing cost.
They show that the mind has little difficulty in preventing such mix-ups between languages. When 26 North American Latino people were asked to read aloud an underlined word within a text that mixed English and Spanish, they did not think longer or make more mistakes than when the text was in a single language.
Gullifer et al. conclude that voluntary language switching is a natural feature of bilingualism that requires little additional processing time by the mind.
Article: http://www.frontiersin.org/Language_Sciences/10.3389/fpsyg.2013.00278/abstract