XI'AN, May 22 -- It's been 2,000 years since emissaries from the Middle East first gathered in Xi'an, the easternmost metropolis on the Silk Road, and Arabic classes remain popular among city residents today.

Every May in Xi'an, capital of northwest China's Shaanxi Province, entrepreneurs, academics, industrialist, politicians and government officials from central Asia and the Middle East gather at the Silk Road International Expo, to talk business and do deals. The fair, which opened on Friday, has very little to do with caravans of camels carrying silk, jewelry and spices these days, but has a lot do with technology, infrastructure and trade.

On the eve of the expo, a motley crew of retirees, college students and businessmen gathered in a downtown Xi'an classroom. They are learning Arabic free of charge, at a school supported entirely by voluntary contributions.

According to the local Arabic translation association, the voluntary school has over 140 students, including local Muslims, Han people from different walks of life, and cultural enthusiasts from Europe and the U.S.

"Our classes have been running for 19 months and we have completed seven semesters," said the school's Hua Tiande. "Four grades of students attend classes three nights every week."

Anyone can sign up. It takes about a year to complete all the lessons and by then, most students will be able to engage in everyday conversation in Arabic, Hua said.

Hua turned the first floor of his home into a classroom to save on rent, but even so, he needs another 8,000 yuan (about 1,300 U.S. dollars) every month to keep the school going.

"Thankfully, donations every now and then keep the school running," said Ma Zhiyuan, a volunteer teacher who learned the language when working in Saudi Arabia.

"I also learned there that language is the key to a foreign market," Ma said. "By learning Arabic, young Muslim's from Xi'an can dream bigger dreams than a snack stall in a tourist street."

Bai Jianbo, director of the Arabic professional board, said Arabic was once a lingua franca along the Silk Road, and will play an important role as the Silk Road Economic Belt takes shape.

Sun Simiao is guest relations manager in a five-star hotel. She receives visitors from Egypt, Saudi Arabia and the UAE almost every day. A Muslim herself, Sun always felt somewhat "distant" when talking with Muslim guests in English.

"I have not been taking lessons for long, but some simple Arabic greetings and small talk are very helpful in the relationship with my guests," Sun said.

Jiao Jie, a railway engineer, often goes to Arabic-speaking countries for survey and design work.

"Friendly contact with local people is a great help to our projects, and the stepping stone is to use their language," Jiao said.

"Language is just a part of Arabic culture. I hope our lessons soon include food, geography and tourism," Ma said, writing the first word of the class on the blackboard: peace.