Those people dismayed that they didn't learn multiple languages as little tykes, when mastering them may have been easier, shouldn't despair entirely, according to new research. Conventional wisdom holds that language acquisition in adulthood cannot rest on the same brain mechanisms used in processing a native language¿that is, a language learned later in life is processed in a fundamentally different and less automatic way than is a mother tongue. But the results of a new study, described in the early online edition of the Proceedings of the National Academy of Sciences, challenge this so-called critical period hypothesis, suggesting that people can in fact process a second language in much the same way as they process their first.

Angela Friederici of the Max Planck Institute of Cognitive Neuroscience in Germany and colleagues first taught a group of adults an artificial language, dubbed BRONCANTO, that has simple yet highly controlled grammar rules. A second group learned the 14-word BRONCANTO vocabulary, but no grammar. The team then monitored brain potential in both groups while the subjects listened to recordings of 488 spoken sentences.

Participants who understood BRONCANTO's rules exhibited very different reactions to sentences containing an error in sentence structure or grammar than did members of the control group: initially, upon hearing a blunder, the electrical impulses to one region of the brain decreased. Then an increase in electrical activity occurred in a second brain region. The findings, the authors write, correspond precisely to the pattern of brain activity commonly thought to reflect automatic syntax parsing in healthy native speakers of natural languages. "Our data," they conclude, "indicate that a late-learned language, in principle, can be processed in a native speaker-like way." They concede, however, that BRONCANTO's small size as a language, and hence the proficiency with which it could be learned, could account for their results and may indicate that language mastery¿instead of the age of acquisition¿determines how the brain processes language.