The acquisition of the first and later languages is highly complex. Some understanding of the brain mechanisms involved are seen in aphasics who have lost part of their faculties for language (from a stroke or other brain diseases). The pattern of recovery is also helpful and has been the subject of many published studies. For those interested, a short review is: A note on aphasia in bilingual patients: Pitres' and Ribot's laws. Eur Neurol 2005;54:127-131