Introduction: Several studies have enhanced differences and similarities in the processing of early and late acquired languages. Anatomic and functional differences have demonstrated how bilingualism exerts executive functions, dependent of the prefrontal cortex in the frontal lobe.
Aim: To study the cortical differences, neurophysiologically measured in school-aged children, in the processing of known and unknown languages.
Subjects and methods: We have measured the recognition processes of words in several languages, specifically Spanish, English, Portuguese and Mandarin Chinese, as well as their event-related potentials (ERP) correlates in 10 year-old children.
Results: The greater knowledge of a language (in our study, Spanish) associates shorter latencies in ERP and a greater activity in both early (N200) and late (N400) components of temporal regions, demonstrating both a direct relation between practice and speed of processing of the language and the consolidation of the linguistic information in the temporal lobe, while less familiar or unknown languages show longer latencies and a greater involvement of posterior brain areas, as well as a different lateralization probably due to a higher effort put on its integration, mostly in late processing stages of linguistic information, which ultimately reflects a clear effect of the neuroplasticity generated by practice, as more efficient and stable neural networks are created after being trained for a long time, in contrast with what occurs with those which have not been sufficiently stimulated.
Conclusion: Mandarin Chinese's organization in the brain cortex shows bilateral with right dominant lateralization as well as longer ERP latencies.