"We might soon send Victor back to Sydney to study," says Xian, a businesswoman. "Australia has more nature and open space, which he misses."

AISG was founded in 1981, originally to teach a handful of children whose parents worked at the city's American consulate. Other early international schools in China catered specifically to expat children and traditionally follow the American or British curriculums.

"English-medium international schools are a vital education provision in major cities," says Nicholas Brummitt, chairman of the Britain-based International School Consultancy (ISC).

ISC reports there are now 530 international schools in China - a tenfold increase since 2000. They cater to the expat population but also the children of Chinese returnees who want to ensure their offspring maintain continuity of English-language learning and a Western curriculum.

Prestigious British schools have been quick to export their elite brands to China, including Dulwich, Harrow, Wellington and Malvern - which have educated noted writers, royalty and former prime ministers.

In 2004, Dulwich opened its first college in Shanghai, and later opened new campuses in Beijing and Suzhou.

"We cannot just transplant a 400-year-old institution to China, but must adapt to the local culture," says Fraser White, founder and executive chairman of Dulwich College International.

The school teaches Chinese as a compulsory subject to students of 45 nationalities - not as an elective second language but a first language on the same level as English. It employs 160 Chinese teachers, who are trained in Western pedagogical methods.

Since 2013, Dulwich has run an ambitious dual-language programme with two teachers in each class. Any particular subject is taught in English and Chinese on consecutive days.

"So far we've seen huge progress and will strive for all our students to attain a high level of Chinese when they leave school," White says. "We cultivate interaction with the students instead of taking the traditional didactic textbook approach."

The bilingual programme is welcomed by expatriate parents, who understand the importance of learning Chinese. It's also been well-received by Chinese returnees, who are anxious their children may lose their edge in Putonghua and their cultural identity in the international school system.

White believes overseas Chinese children who shun Putonghua may have had a poor didactic learning experience. "So we make it fun for our children to learn Chinese," he says.

Communications director Lawrence Cook says: "We take the best of the UK's teaching philosophies and frame within them the richness and diversity of the local culture.

"As guests in China, we help our kids appreciate and empathise with different cultural perspectives, social practises and religious beliefs."

Although Dulwich has received a number of enrolment inquiries from Chinese parents, it is only permitted to admit students with overseas passports. (Local students can, however, study at Dulwich's two affiliated international high schools, in Suzhou and Zhuhai.)

Unsurprisingly, many of China's wealthy middle class are keen to enrol their children in international schools; it is a status symbol as much as a pathway for their children to study overseas.

As demand has risen, the market has diversified into new categories of joint-venture schools such as those set up by local investors and foreign education brands, Chinese private schools, and international sections of local high schools.

While foreign international schools offer the choice of Advanced Placement, the International General Certificate of Secondary Education or International Baccalaureate Diploma programmes, their local counterparts incorporate a Western curriculum into the Chinese National Curriculum programme.

Education providers are also branching out into vibrant second-tier cities, which are eager to attract foreign investment and quicker to approve new international schools than Beijing or Shanghai. Britain-based Wellington College chose Tianjin as the site of its first mainland school, which opened in 2011 in the new Bund district. Malvern College has two schools, in Qingdao and Chengdu, while United World College's new Changshu campus in Suzhou opened in September. Next year, Harrow will open another school in Shanghai in addition to its schools in Beijing and Hong Kong, ISC reports.

Investors are pouring millions of dollars into building slick campuses equipped with hi-tech classrooms, state-of-the-art libraries and sports facilities, hiring world-class teachers and developing educational resources. That's why, although state education is free, international schools charge annual tuition fees ranging from 60,000 yuan (HK$73,000) to 260,000 yuan.

"It's a great challenge to provide high-quality education and maximise profit at the same time," says Michael Ludwick, former AISG development director and founder of the Near West cultural arts group.

Traditional non-profit schools such as the AISG are governed by a volunteer board with no shareholders to pay. All earnings are reinvested in the school so management can focus on providing the highest quality education without having to earn value for investors.

Ludwick cautions that when schools grow rapidly for a profit, it can significantly compromise the school culture, education quality and outcome for students. It could, for example, lead to a high turnover of teachers if management fails to invest enough in them.

"The only way to ensure a consistently excellent and evolving international school is to invest heavily in teachers. Every yuan paid to shareholders could have been used to recruit and retain professional talent and improve school facilities," Ludwick says.

"The good schools realise that the most effective way to earn value long-term is by providing a quality educational product. And there are many examples of such schools."

The growing popularity of international schools in China reflects not only the country's economic rise but also the fact that Chinese have long been passionate about learning English, which is regarded as an important key to success. Before the elite schools came along, people found other ways to fulfil their dream of studying overseas.

Dong Xiaoxi, from a working-class family in Xian, started learning English at the age of 13, when she entered Xian's Five Ring Middle School, which was affiliated to her parents' factory. Two years later, she met a young teacher who changed her life.

"Ms Ma taught very creatively and always encouraged us. We'd write a journal or translate a classical Chinese poem into English. She praised us whenever we used good vocabulary. We didn't feel any pressure at all," says Dong, who remains close friends with Ma.

Outside class, Dong read English novels and listened to , the popular American radio broadcast that taught generations of mainland English speakers. Dong speaks fluent English without the slightest hint of an accent.

She majored in English at Xian's Xibei University, graduated with honours, and was awarded a master's scholarship for American studies by Guangzhou's prestigious Sun Yat-sen University. On completion, she returned to teach at the Xian International Studies University for seven years until 2013, when she'd saved enough money to undertake her PhD studies on Afro-American literature at University of Hong Kong.

Last year, she first set foot on American soil when she attended a conference in Oklahoma. This year, she obtained the Fulbright scholarship to become a visiting scholar at University of Massachusetts at Amherst for a year.

Dong travelled a longer road than more privileged Chinese students, but arrived at her destination all the same without spending a fortune.