In Ms Lei's case, her Malaysian-Chinese mother had pushed her to study in China, even though she originally resisted. 'I think Chinese people always have the dream to send their children back,' said Ms Lei. 'At first I wasn't willing to accept my mother's ideas, but I tried my best to do some research on China, and then I thought: 'OK China's not that bad.' So I decided to come as a challenge,' said Ms Lei, whose father is a Myanmar-born Chinese.

The numbers of overseas-born Chinese, sometimes referred to as hua qiao (literally Chinese person), studying in China are hard to come by. The Ministry of Education and universities provide numbers of nationalities studying here but not breakdowns of their ethnic backgrounds.

But anecdotal evidence suggests it's a big trend. At the Beijing Language and Culture University (BLCU), one of China's best known language schools, an official in the foreign-students office said the numbers were growing larger every year. 'They come from everywhere,' she said - including North America and South America, and Europe as well as Africa and across Asia.

'Their parents are all Chinese, and the children can't speak Chinese and they want to their kids to speak their language.'

The hua qiao are part of the overall boom in foreign students in China. Last year, the mainland hosted more than 110,000 foreign students from more than 178 countries, the highest number ever.

It might not be surprising that these young overseas-born Chinese are coming back to the land of their forebears. After all, when the Chinese started emigrating abroad in large numbers in the late 1800s, most planned to get rich abroad and then return home. While few ever realised those dreams, there is still a deep desire by many Chinese emigrants to return.

Numbers also help. The Chinese diaspora is huge, estimated at 33 million or more which means there is a big supply of potential students.

Growing up, Ms Lei had a typical experience as a daughter of immigrant parents. She tried hard to fit in with her carefree, easygoing Brazilian friends while at the same time trying to obey her more traditional mother.

'It was not very easy,' Ms Lei said. 'Although I was born there, people tried to recognise me as Chinese. I insisted on being Brazilian.' After her mother started sending her to Chinese school, she began to understand Chinese culture, and the origin of her ethnicity.

Many other overseas-Chinese students expressed the same desire. Singaporean-born, British-raised Oliver Lo, who graduated last year from Cambridge University, said he wanted to make up for years of living in the UK.

'I didn't want to start working straight after finishing university,' said Mr Lo, 22. 'I picked China just because my whole life I felt pretty un-Chinese, especially because all my friends can speak Cantonese,' said Mr Lo, a student at the private Diqiucun language school, in the Wudaokou university district.

One of Mr Lo's friends, Eric Ching, 22, moved for pretty much the same reasons. 'I decided to write down a few things I wanted to do and it seemed Chinese would be the most practical and most sensible thing,' said Mr Ching, who is from California.

Mr Ching's experience illustrates the powerful grip that Chinese culture has on emigrants and their descendants. He is a fifth-generation Chinese-American who considers himself 'more American than a lot of Americans' and whose grandfather was the first Chinese to teach English in California.

But Mr Ching, who is studying at BLCU, also feels a desire to become more Chinese. 'Many of my friends and those who I hang out with in the United States are Chinese or expect me to know the language. It was always a strange burden that I didn't know Chinese.'

Once in China, their experiences are usually no different from their other foreign counterparts. Most students live and study in the Wudaokou district, a sprawling northwestern suburb of Beijing, filled with university campuses, high-rise apartment complexes, a light rail line and a burgeoning night life scene.

They spend their days attending class, learning characters and trying to pronounce new words. For some, being Chinese may give them an advantage over their classmates: thanks to their parents they may already be familiar with basic words or grammar.

But as often as not, these hua qiao students are starting from scratch. And they also get a lot less slack compared with more visible Westerners, said Walter Cua, 25, a student from New Jersey. 'If you're a white guy and you're trying to speak Chinese, they're more tolerant,' said Mr Cua, whose parents emigrated to the US from China via the Philippines.

'But if you're Chinese and you can't speak the language they won't put up with it. It's much more respectable for a white person to learn Chinese,' he complained. Unlike the others, Mr Cua said it was not his choice; his parents made him come to learn Putonghua in the hopes that he might one day take over the family seafood business in New Jersey.

Aline Wong, 20, has also encountered reverse racism.

Ms Wong, from Mauritius, a small island nation in the Indian Ocean, won a four-year scholarship to Shanghai's Tongji University. 'Some salesmen, thinking that I'm Chinese from China, talk a bit rudely to me at first but once they hear me speak Creole to my Mauritian friend, they are very surprised and at once speak more nicely,' she said. 'I also feel my teachers expect more from me because of my background.' Her parents are Hakka people from Guangdong who emigrated to Mauritius 30 years ago and can't speak any Putonghua.

Still, the students all say they like living in China and hope to find work after they finish studying, including Mr Lo, who wants to break into advertising, and Ms Lei, who is thinking of starting an import-export company.

And have they succeeded in getting in touch with their roots? 'I cannot say that I feel more Chinese,' said Ms Wong. 'I already felt Chinese when I was in Mauritius. It's just that here, I've learned more about the Chinese culture and history. I feel really comfortable.'