His parents Melindie and Duncan claim Caleb, who was diagnosed with profound hearing impairment in both ears at six weeks old, uses his device to listen in on everyone's conversations.

"He's quite a cheeky little man - a bit of a busybody," Mr Best said.

"He overhears conversations all the time. The other day we were talking about making apple crumble and then Caleb - who was two rooms away - piped up with 'I want some'."

That their son is now able to hear at all is cause for joy for the Illawarra couple and their two daughters, Ebony, 7, and five-year-old Matilda.

The family enjoyed an open day at the Wollongong branch of The Shepherd Centre yesterday during Hearing Awareness Week and said they owed a lot to the First Sounds Cochlear Implant Program run by the organisation.

"When Caleb was two days old, he had the newborn hearing test done in hospital - they did it three times just in case it was the equipment that was failing, not Caleb's hearing," Mrs Best said.

"He was referred to the hearing clinic at the Sydney Children's Hospital when he was six weeks old. When the audiologist told us Caleb was deaf, I just burst into tears.

"He got hearing aids but they weren't enough for him so when he was 18 months he got the cochlear implant and additional help from The Shepherd Centre and that made such a big difference - it's changed his life and ours."

The centre helps Caleb - and about 300 other NSW babies and children born deaf or hearing impaired - with the management of the cochlear implant from the initial programming to its ongoing use and associated learning.

"We have auditory and verbal therapists, child and family counsellors and an audiologist.

"We want these children to be able to integrate into society, to attend mainstream schools and live full, active lives like their peers," said Danielle Slack, a senior listening and spoken language specialist at The Shepherd Centre

The Bests said Caleb was well on track thanks to the program and would be joining his sisters at their local primary school in two years' time.

"He's now in the typical range for his receptive [listening] and expressive [speaking] language skills," Mr Best said.

"His speech intelligibility is nearly on par and he's fast catching up."

Meantime, little Caleb takes it all in his stride.

"He has a cochlear implant and has to wear hearing aids and also glasses due to an astigmatism in his left eye, but he's such an easygoing boy," Mrs Best said.

"He just enjoys playing with his sisters, and just enjoys life in general."