Why learning a new language may make you forget your old one
Traveling abroad presents an ideal opportunity to master a foreign language. While the immersion process facilitates communication in a diverse world, people are often surprised to find they have difficulty returning to their native language. This phenomenon is referred to as first-language attrition and has University of Oregon psychologist Benjamin Levy wondering how it is possible to forget, even momentarily, words used fluently throughout one's life.
In a study appearing in the January, 2007 issue of Psychological Science, Levy and his colleague Dr. Michael Anderson discovered that people do not forget their native language simply because of less use, but that such forgetfulness reflects active inhibition of native language words that distract us while we are speaking the new language. Therefore, this forgetfulness may actually be an adaptive strategy to better learn a second language. In the study, native English speakers who had completed at least one year of college level Spanish were asked to repeatedly name objects in Spanish. The more the students were asked to repeat the Spanish words, the more difficulty they had generating the corresponding English labels for the objects. In other words, naming objects in another language inhibits the corresponding labels in the native language, making them more difficult to retrieve later.
Interestingly, the study also showed that the more fluent bilingual students were far less prone to experience these inhibitory effects. These findings suggest that native language inhibition plays a crucial role during the initial stages of second language learning. That is, when first learning a new language, we have to actively ignore our easily accessible native language words while struggling to express our thoughts in a novel tongue. As a speaker achieves bilingual fluency, native-language inhibition becomes less necessary, accounting for the better performances of fluent bilingual speakers in the study. Although the value of suppressing previously learned knowledge to learn new concepts may appear counterintuitive, Levy explains that "first-language attrition provides a striking example of how it can be adaptive to (at least temporarily) forget things one has learned."