“Kypy, käpy, titi, pipö, pöpö,” says the voice in my headphones, sounding like a broken robot trying to compose a poem in Finnish, but this is a brain study focusing on language learning.
Just moments earlier, Lilli Kimppa, a doctoral student of psychology, affixed a cap with electrodes onto my head to measure EEG while I watch a muted cartoon on a screen and listen to a recording of words and nonwords on headphones.
The experiment is part of Kimppa’s dissertation research, in which she measures the neural response dynamics to new words among young adults.
“This response coincides with word recognition points. This means that when we hear a word, we can recognise it before we hear it in its entirety," Kimppa explains.
The more familiar the word, the stronger the response in the EEG.
Kimppa’s dissertation supervisor, Professor Yury Shtyrov and his colleagues, discovered a rapid increase in the brain response to new words while the response for familiar words attenuated within a short exposure in earlier studies. This discovery has been suggested to reflect the formation of memory circuits for the novel words in the brain, i.e., the process of learning a new word.
In Kimppa’s research setting, the research subjects listened to sounds which could be native Finnish words as well as sounds which were phonologically non-native. The brain response was measured in both active and passive listening sessions where the same word was repeated 150 times.
In passive listening, the subjects watched a muted film and were instructed not to pay attention to the sounds coming from their headphones. In active listening, the subjects were asked to memorise the words and press a button when they heard a target sound.
“We found in a previous study that the increase in response correlated with the extent to which the subject could later remember the words.”
“The response increase to new wordforms with Finnish phonology was much greater than for wordforms that featured foreign elements. Then I noticed that there was more variance in the response dynamics for the novel non-native wordforms,” Kimppa describes her research results.
Language learning can influence brain plasticity
When Kimppa examined the background information of the research subjects, she found that subjects who built new memory circuits for the new non-native wordforms faster according to their brain responses had studied more languages and had started learning them at a younger age on average.
It should be noted that all subjects had only begun learning languages at the average age of nine in school.
“Research indicates that learning a language is easiest before the age of seven, but our results suggest that starting learning later in childhood can still influence brain plasticity and the ability to learn new things in adulthood."
An unexpected result of the research was that the later the subjects had begun to study languages, the more intense was their brain response enhancement to new words with Finnish phonology.
“Their brain had apparently become more attuned to native language, while those who had studied multiple languages with earlier learning onset age had more flexible neural networks to take in foreign elements and merge them into the existing networks,” Kimppa says.
Extensive language circuits may help brain-damaged patients
In the future, Kimppa intends to repeat the study on aphasia patients, who have impaired speech production and comprehension due to damage in the left brain hemisphere.
“I’m interested in how the brain can learn new things after sustaining damage, and which areas of the brain enable the learning of new linguistic material when the primary areas have been damaged,” Kimppa states.
“People who are proficient in several languages have more extensive language circuits in their brain, so one could hypothesise that their brains would be better equipped to relearn language. Meanwhile, the native language is processed in very efficient, highly automated systems, and its neural circuits are more centralised.”
Research article ”Individual language experience modulates rapid formation of cortical memory circuits for novel words” by Lilli Kimppa, Teija Kujala and Yury Shtyrov was published in Nature’s Scientific Reports series.