Teacher Aliena Gerhard conducts online English classes for her Chinese students on the other side of the globe, but she feels much closer to them.

"One of the greatest moments for me ... was when my student's mom had her third child and I was brought into the delivery room. So I got to see the baby the day it was born," Gerhard said.

"I felt like part of the family and it was just such a blessing to me."

Gerhard, 47, lives in the US state of Vermont. For the past two years, she has been holding one-on-one classes, six days a week, with students in China. Gerhard's first student, named Bright, was the one who "took" her to his mother's delivery room through a live streaming online class.

"You know you might just be teaching a child halfway across the world on a screen, but it doesn't divide you," Gerhard said.

"It's just you feel that bond when you connect with the child and you feel the bond with their family and you just become a part of each other's lives."

Gerhard is one of more than 70,000 teachers in the United States and Canada who work for Chinese online education services giant VIPKid, which boasts more than 600,000 students since its rollout six years ago.

Before she taught online, Gerhard, who has a doctorate in law, worked as an attorney.

"I used to protect children. People that would hurt children, I would prosecute them and have them sent to jail," Gerhard said.

Since she started working with VIPKid, Gerhard's daily routine includes spending time with her own children at breakfast and home-schooling them.

Gerhard said her work with Chinese students helps both sides "understand each other's cultures".

Michelle Yang, the education company's head of teacher recruitment, said, "When the company started, there were very few people who had ever heard of online education, let alone were willing to pay for it."

More parents gradually came to know about the group's online education services, with those from major cities registering and becoming its early users, Yang said.

The online English-learning trend for Chinese children seems set to continue: More than 15 million users signed up for the services last year, growing nearly 200 percent year-on-year, with the size of the market set to surpass 50 billion yuan ($7.3 billion) by the end of this year, according to mobile internet big data monitoring platform Trustdata.

Huang Jinyan, 36, an advertising executive from Suzhou, Jiangsu province, said she enrolled her 9-year-old son in English online classes because of the increasing convenience they offer as home learning platforms.

She paid about $2,000 for a course of 80 sessions, including one-on-one classes of around a half-hour each that allowed her child to "interact directly with the teacher" through headsets, microphones and video-streaming via computer.

"It's quite intensive, even from the comfort of home. The programs track his progress quite effectively," Huang said. "I guess it's as close to being face-to-face as possible nowadays."

Yang from VIPKid said advances in technology are rapidly closing the gap between online and traditional learning.

"Our students can learn whenever and wherever they want, and they don't have to spend time on commuting. Most important, they are learning English with native speakers with rich teaching experience. They are talking to people with different cultural backgrounds," she said.

With developments in the fields of artificial intelligence and big data, the company is also tapping facial recognition and other technologies to "capture and analyze the learning data of users in class. We also observe the interaction frequency between teachers and students, so as to improve the teaching content and children's focus and concentration", Yang said.

Huang conceded there is still criticism that traditional classrooms are "irreplaceable", and there are concerns about an overemphasis on virtual platforms, but like many users and supporters of online learning, she is confident that the latest technologies can help offer more personal forms of learning than one teacher taking care of one class of students.

Li Hongye, a software engineer whose company, Jindai Systems, develops applications for online learning portals, said that since virtual reality technology is using increasingly fast and sophisticated communication networks, the "possibilities for the sector are also endless".

"We're racing to fill the growing technological demands from these 'borderless classrooms'," he said. "In that regard, education really is becoming global and bringing people closer together."