Cognitive psychology- language

  The Tanaka family emigrated to Canada from Tokyo 10 years ago and learned to speak English upon arrival. Machiko was 14 years old at the time and speaks English quite well, but with a bit of a Japanese accent. She also confuses “r” and “l” sounds. Her parents speak English less well than Machiko, and with a pronounced Japanese accent. But Machiko’s youngest brother Shuji was only a baby when the family arrived in Canada and speaks English perfectly, and with a native Canadian accent. He is also able to easily discriminate between “r” and “l” sounds.   What does this tell us about how we acquire new languages? What do these differences indicate about how we develop regional accents and our ability to discriminate between different speech sounds? Are there other challenges besides proper pronunciation for adults learning a new language? Do you think knowing two or more languages is beneficial?