The anatomical changes associated with language learning appear to be reversible, though. One brain scanning study found that adult Japanese speakers who took a six-week English-language course had increased gray matter density, compared to controls, in certain language regions of the brain. Follow-up scans performed a year later revealed even bigger increases in those who had kept up their language practice. In those who had stopped, however, gray matter density in the affected brain regions had returned to pre-training levels.
