The ability of bilinguals to switch seamlessly between two languages, even while in the middle of a conversation, has long been a much-admired skill. Now researchers from Arizona believe they have pinpointed the process that allows them to do this. The University of Arizona research, which is to be published in the Association for Psychological Science‘s journal Psychological Science, has discovered that those who have been brought up speaking two languages are able to identify and differentiate between the different sound systems of each language. This allows them to switch between the two. Differentiating the two Researchers worked with 32 bilingual English and Spanish speakers who had begun to learn their second language before turning eight years old. The researchers gave participants a list of made-up words known as pseudowords that started with either “pa” or “ba”. Volunteers were then split into two groups; with one half told they would hear a list of rare English words and the other that they would hear unusual Spanish words. In fact, they both heard the same list, although the pronunciation was altered to match the language the listener believed they were hearing. The way these two sounds are pronounced is slightly different in English compared to Spanish and the subjects were asked to identify which sound they heard as the list was read to them. Spanish speakers produce the “pa” sound in a similar way to the English pronunciation of “ba”. This is a sound that English speakers will produce through a vibration of their vocal chords as they open their lips, while in Spanish the chords begin to vibrate just before the lips are parted. Meanwhile, the Spanish pronunciation of “pa” is similar to that of “ba” by English speakers. Whether they thought they were listening to English or Spanish was found to influence how the participants perceived the “ba” and “pa” sounds they were hearing. The study was then repeated on those who only speak English and this shift in perception was not apparent, whether subjects were told they were hearing English or Spanish. As a result, the researchers – headed up by lead author and psychology doctoral student at the university Kalim Gonzales – concluded that bilingual speakers must have two separate modes, or sound systems, that they use to differentiate between the languages they are hearing. This gives them the ability to switch seamlessly back and forth between the two. Listening like a native Prior to the study, it was suspected that such sound systems existed, although another suggestion was that bilinguals recalibrate their hearing to the unique acoustic characteristics of the different languages. The new research appears to disprove this theory and support the existence of separate modes to process the speech of each language they speak. It means that bilingual people perceive both the languages they speak in the same way as a native would. “This is one of the first clear demonstrations that bilinguals really do have two different sound systems and that they can switch between one language and the other and then use that sound system,” says Andrew Lotto, co-author and the university’s associate professor of speech, language and hearing sciences. Interestingly, Lotto explains that the use of separate sound systems as a guide only seems to be apparent among those who learn a second language while they are young. Among linguists who study languages later in life, one sound system – the one for their mother tongue – appears to be used in the perception of both languages. It is for this reason that people who learn a second language when they are older speak it with an accent. What’s the best age to learn a new language? It may be that this is why the most effective age at which to learn a second language is early childhood, with many researchers suggesting that before the age of six or seven is the prime time. This is when a person’s language acquisition abilities are at their best, which makes picking up and maintaining a second language easier. Bilingual speakers who learn at a young age are also likely to be able to talk in the second language free of their native accent. However, that doesn’t mean adults should abandon all hopes of learning a second language. Anne Merritt, English as a foreign language lecturer, wrote in the Telegraph that the key to mastering speaking a second language is to get the pronunciation right, rather than worrying about the accent. Her comments echo a study by Murray J Munro, linguistics professor at Canada’s Simon Fraser University, and Tracy Derwing, linguist at the University of Alberta, which was reported in Time. In it, the researchers claimed there was a “nativeness principle” – where speakers believe they have to ape an accent perfectly when speaking in a second language – that needs to be replaced with an “intelligibility principle”. This means making how well the person is understood in the second language their priority, rather than how authentic they sound. How long have you been speaking a second language for? Do you find it easy to switch between the two?