The robots, which display an avatar face of a Caucasian woman, are controlled remotely by teachers of English in the Philippines — who can see and hear the children via a remote control system.
Cameras detect the Filipino teachers' facial expressions and instantly reflect them on the avatar's face, said Sagong Seong-Dae, a senior scientist at KIST.
"Well-educated, experienced Filipino teachers are far cheaper than their counterparts elsewhere, including South Korea," he told AFP.
Apart from reading books, the robots use pre-programmed software to sing songs and play alphabet games with the children.
"The kids seemed to love it since the robots look, well, cute and interesting. But some adults also expressed interest, saying they may feel less nervous talking to robots than a real person," said Kim Mi-Young, an official at Daegu city education office.
Kim said some may be sent to remote rural areas of South Korea shunned by foreign English teachers.