In a cafe in south London, two construction workers are talking cheerfully. They sometimes break into loud laughter. They are discussing something, and their conversation looks fun and interesting. But I don't speak their language. Out of interest, I interrupt them.
With friendly smiles, they both change easily to English, explaining that they are South Africans and were speaking Xhosa. In Johannesburg, where they are from, most people speak at least five languages, says one of them, Theo Morris. "My mother's language is Sotho. My father's is Zulu. I learned Xhosa and Ndebele from my friends and neighbors, and English and Afrikaans from school. I can speak well all of the languages mentioned above. I went to Germany before I came here, so I also speak a little German," he adds.
"Is it easy to learn so many languages?" "Yes, it's normal," he laughs. He's right. Around the world, more than half of the people speak at least two languages. Many countries have more than one official language — South Africa has 11. People, young or old, are increasingly expected to speak, read and write in at least one of a handful of "super" languages, such as English, Chinese, Hindi, Spanish and Arabic.
Multilingualism（多语言）has many social psychological and lifestyle advantages. Moreover, many health benefits from speaking more than one language have been found, including faster stroke (中风) recovery.
Could it be that the human brain evolves (进化) to be multilingual — that those who speak only one language are not realizing their full potential? And in a world that is losing languages faster than ever — one every two weeks, half our languages will disappear hopelessly by the end of the century. What would happen if the rich diversity of languages disappeared and most of us ended up speaking only one? That's a serious problem we are facing.
