UA Research Demonstrates How Bilinguals Switch Between Languages

The UA findings challenge the idea that bilinguals always have one dominant language. "This raises the possibility that bilinguals can perceive speech like a native speaker in both languages," said Gonzales.
May 21, 2013


According to US News and World Report, the UA graduate program in speech-language pathology ranks number five in the United States. The program resides in the School of Mind, Brain and Behavior in the College of Science.

This new research, to be published in Psychological Science, addresses enduring questions in bilingual studies about how bilingual speakers hear and process sound in two different languages.

Two Views on Bilingual Switching

"A lot of research has shown that bilinguals are pretty good at accommodating speech variation across languages, but there's been a debate as to how," said Kalim Gonzales, UA psychology doctoral student and lead author on the study. "There are two views: one is that bilinguals have different processing modes for their two languages – they have a mode for processing speech in one language and then a mode for processing speech in the other language. Another view is that bilinguals just adjust to speech variation by recalibrating to the unique acoustic properties of each language."

Gonzales's research supports the first view – that bilinguals who learn two languages early in life learn two separate processing modes, or "sound systems."


While 'pa' and 'ba' sounds exist in both English and Spanish, how those sounds are produced and perceived in the two languages varies subtly. In the case of 'ba,' for example, English speakers typically begin to vibrate their vocal chords the moment they open their lips, while Spanish speakers begin vocal chord vibration slightly before they open their lips and produce 'pa' in a manner similar to English 'ba.' As a result of those subtle differences, English-only speakers might, in some cases, confuse the 'ba' and 'pa' sounds they hear in Spanish, explains Andrew Lotto, UA associate professor of speech, language and hearing sciences and the study's co-author.



Mode Makes the Difference

For the study, the bilingual participants were divided into two groups. One group was told they would be hearing rare words in Spanish, while the other was told they would be hearing rare words in English. Both groups heard audio recordings of variations of the same two words – bafri and pafri – which are not real words in either language.






"Up until this point we haven't had a good answer to whether bilinguals actually learn two different codes – so a 'ba-pa' English code and a 'ba-pa' Spanish code – or whether they learn something that's sort of in the middle," Lotto said. "This is one of the first clear demonstrations that bilinguals really do have two different sounds systems and that they can switch between one language and the other and then use that sound system."


"If you learn a second language later in life, you usually have a dominant language and then you try to use that sound system for the other language, which is why you end up having an accent," he said.         

Research on bilingualism has increased in recent years as the global climate has become more intermixed, Lotto notes. The UA findings challenge the idea that bilinguals always have one dominant language.

