The Bilingual Brain
This event provided linguistic and neuroscientific insights on the differences between learning a second language in youth and adulthood.
In today's globalized world, multilingualism is common, relevant, and to many, a necessary part of daily life. Research into the neurobiology of bilingualism has shown that people who speak more than one language fluently have an advantage over those who are monolingual - and not just in terms of communication skills. Scientists have found that regardless of the age of acquisition, bilingual people have increased brain density, which leads to improved skills and abilities. People who become bilingual early in life often show better concentration and are less prone to distractions. They also may be better protected against dementia and other age-related cognitive decline.
On June 3, the German Center for Research and Innovation (GCRI) hosted a Science Dinner and discussion on second language acquisition and the role of memory systems in the brain as they relate to first and second language acquisition. Linguistics Professor Jürgen M. Meisel (University of Hamburg & University of Calgary) spoke about the simultaneous and successive acquisition of bilingualism and the age of onset of second language acquisition in early childhood. Comparisons of monolingual (L1) and multilingual (2L1) first language development have demonstrated that children exposed to two or more languages from birth are able to develop a native grammatical competence in each of their languages. Meisel presented evidence that linguistic systems are differentiated at an early age and that grammatical development proceeds through the same developmental sequences as in monolinguistic acquisition. When learning a second language, age does matter: Studies have found that important linguistic and neuropsychological competencies emerge between the ages of three and a half and four years.
According to Meisel, successive acquisition of languages (L2) results in qualitative differences. He also posits that very few L2 adult learners reach a native speaker’s level: “My hypothesis is that with increasing age, parts of the human Language Making Capacity (LMC) become inaccessible as a consequence of neural maturation.” Therefore, L2 learners have to resort to other cognitive resources to compensate.
The declarative and procedural memory systems, which were presented by Professor Michael T. Ullman, are distinct cognitive systems which have distinct roles in language acquisition and involve different neural circuits. The estrogen-influenced declarative system is used for learning and processing facts and events: “Estrogen improves the clarity of memory,” Ullman said. The procedural system is used for learning cognitive and motor skills, as well as implicit knowledge acquisition. The procedural memory system, which is less well understood than the declarative memory system, is located in the left side of the brain, and is influenced by the neurotransmitter dopamine. Ullman, who teaches in the departments of Neuroscience, Linguistics, Psychology and Neurology at Georgetown University, agreed with Meisel that L2 learners rely primarily on the declarative system for grammatical processing, whereas L1 speakers rely on the procedural system. He, however, argued that increased language proficiency leads to heightened interactions between both memory systems. Cooperatively, they are redundant mechanisms, where “both can learn the same types of knowledge or skills, but with different computational and neural bases.” When “dysfunction of one system can enhance the functionality of the other,” both systems act competitively. Other factors, such as sex, handedness, amount and type of exposure to the language, as well as hormonal and genetic background influence a person’s ability to learn a second language. Based on his studies, children learn languages with procedural memory. Older language-learners rely more on the declarative system – and the higher the estrogen level, the better information can be retained.
When asked about the best age to learn a second language, both speakers agreed that it should be “no later than age three.”