To show Jian how his vocal cords and tongue worked, they put his hands on their throats and tongues so he could feel every syllable.

To teach Jian the word for "cattle", his first word, they took him to see a herd each day and told him, "Niu!"

Xu Zhihong said one occasion is burned into his memory. As the family sat on a slope, waiting for the herd to show up, a heavy sadness washed across him. He could hear the babbling of a brook down the hill, birds chirping in the trees, leaves rustling in the evening breeze. But in his 19-month-old son's world there was just silence.

Jian's breakthrough came three months later, on July 15, 1996, when he uttered the word niu. His parents were thrilled, knowing that the notes and labels they had pinned and stuck everywhere at home were working.

Within a year, Jian had a vocabulary of 300 words and was able to hold simple conversations.

Just as the family was celebrating its success, a cruel twist of fate came again. In the summer of 1997, Kang caught a cold and was left deaf by an adverse reaction to medicine. He had learned to talk by then, but his vocabulary was limited. Pulling themselves together, the couple began to teach Kang in the same way as Jian, with the same dedication.

The parents, both primary school teachers, struggled to make ends meet. They sold almost everything they owned and moved a dozen times for cheaper rents.

They channeled all their focus on teaching their sons, using methods they created themselves. They managed to scrimp and save to pay for a cochlear implant for Jian in 2006 and later a hearing aid for Kang, whose hearing loss, while severe, was not as profound as Jian's, and the two boys went on to attend mainstream schools.

Helping others

Soon after the parents helped their sons talk, others began knocking on the door of their Huocheng county home, asking for help. The couple did not turn anyone away, and became well-known among parents of children with hearing defects.

Over the past two decades, they have helped and inspired more than 200 children, who still affectionately call them Papa Xu and Mama Zhou.

Xinjiang, home to 47 ethnic groups, has more support for disabled children nowadays, but special education schools still lack enough teachers who can speak both Mandarin and at least one local ethnic minority language.

In 2000, four-year-old Lu Yanzi was brought to the couple for help. Xu Zhihong agreed without hesitation. "I wanted to help the family, just as many people had helped me," he said. "Looking at the yearning in their eyes, how could I refuse them?"