Learning a new language makes you forget other languages

Learning words in a new foreign language makes it more difficult to remember those same words in another foreign language. That is the conclusion of a research study by Kristin Lemhöfer, Psycholinguist at Radboud University and The Donders Institute, and her colleagues. For the first time, a situation for which there was only anecdotal evidence was replicated under controlled conditions. 'You sometimes hear people say that they used to be good at French until they started learning Spanish,' says Kristin Lemhöfer. 'We wanted to find out what actually happens at such moments and whether we could mimic this process in the lab.' Participants were first tested on their word knowledge: they were shown pictures, asked for the English word for what they saw, and then asked to learn half of the English words they already knew in Spanish as well. 'We checked immediately afterwards to see whether those English words had become less accessible. In particular, we saw that the speed with which test subjects came up with the words had decreased.' Sleep.