Heartbroken, the couple decided to set up the centre in their son's memory, calling it Benji's Centre.

"His death left a big hole in our lives. Because he used to suffer from speech delay, we wanted to help children like him. Setting up the charity became a kind of therapy for us," Wong says.

Wong and his wife have a trading business that also operates factories on the mainland. As entrepreneurs, they realised the speech centre needed sustainable funding, so they launched a food business, Confiserie Benji.

Starting in 2002, as the distributor for a brand of Belgian chocolates, it has grown to include five chocolate shops, a Japanese restaurant, a French restaurant, and workshops in Hong Kong making cakes and cookies under their own brand, Benji's.

"We had never run a food business before but it has got bigger and bigger," Wong says. "When we got the idea of setting up a charity, we knew that our savings could only keep it going for two to three years. We needed to come up with a business to bankroll the charity. … All of the HK$6 million annual cost for running the charity came from the food business."

The only non-governmental organisation focused on speech therapy, the centre initially occupied a small venue with two treatment rooms in Tsim Sha Tsui, serving 80 children. Needing to expand, they quit the space and now run two big centres in Sha Tin and Nam Cheong, which now serve 350 children between them.

But the couple find they still need to seek grants from The Community Chest and government, as well as organise donation drives.

"When we looked for special-needs services for Benjamin, we knew there was a severe shortage of publicly funded training places for children with speech problems. You had to queue for one to two years for a consultation," Wong says. But the golden period for helping a special-needs child to catch up with his peers is up to six years old. We want to help plug the gap in provision of services."

Their two centres employ 13 speech therapists who help children up to 16 years old.

Seventy per cent of children are treated for free, with the remaining paying HK$300 for each 45-minute one-on-one session with a therapist. That is substantially cheaper than in the private sector, where one session may cost HK$1,000.

Wong and his wife know how timely therapy can change a child's life. Benjamin was born with a mild form of Down's syndrome and suffered many health problems including weak muscles and lungs. The couple spent more than HK$10,000 each month on various treatments for their son.

And it was the speech therapy sessions that helped Benjamin the most, Wong says.

"When he was a year old, he caught a cold which became so serious that he was in intensive care for four months. He nearly died from the ordeal. After that, we gave him lots of treatment including physiotherapy, cognitive therapy and speech therapy. He was diagnosed as lagging behind his peers in speech development by a year.

"His speech delay was caused by weak oral muscles. Exercises like blowing soap bubbles and chewing plastic helped strengthen his oral muscles. Since he received training at the age of two, he showed marked improvement," Wong says.

"Because he couldn't speak well at first, he used to be shy and hung his head when meeting strangers. But by the time he was in kindergarten, he opened up. He even began talking back to us. For a child, the ability to express oneself clearly is a huge confidence booster."

Wong adds that speech disorder is caused by many factors such as weak muscles among children with Down's syndrome and autism, "which results in poor articulation skills and parroting behaviour". Some patients at the centre "suffer from brain paralysis which causes developmental delay".

"We won't discharge a child until he can talk as well as his peers," Wong says. "Some children have been with us for eight to nine years. Government services only serve special-needs children up to age six. but we help teenagers, too."

Getting the children to perform in public has become another form of treatment at their centres. The programme began last year and they have 24 performances scheduled this year, Wong says.

"We teach the children to sing and arrange for them to perform in malls. Parents are touched by the marked improvement in their children. Some were dribbling and barely able to complete sentences a year ago. Yet they were able to sing and play so confidently on stage.

"Performances in malls can also make the public more aware of the importance of getting prompt treatment for speech disorders. Many parents think it's normal for kids to have speech delay and overlook the problem. Many parents who later enrol their children with us come to us only after seeing the performances in malls."

Wong and Ho have a proven track record when it comes to a philanthropic-minded approach to business, underscored by their Christian values.

During the economic downturn in the late 1990s, for example, they set up an assistant position at their trading company specifically for middle-aged people (only people above 40 could apply) who had been unemployed for three years.

The job only lasted for three months, but they helped several people regain their confidence and sense of purpose.

Their food business takes a similar approach.

"The staff we employed at the beginning were troubled youths and people with depression," says Ho. "Instead of asking underperforming staff to leave like other companies would, we wanted to give them another chance. Once they overcome the obstacles, we believe they can perform their jobs well, too."