The more words a child hears from birth, the better their language will be. Parents are encouraged to begin chatting to their babies as newborns, and most trust that when they go back to work, child care staff will do the same.
But a new study from Macquarie University has found that child care centre workers vary wildly when it comes to how much they talk to babies and toddlers, ranging from 50 words per minute at some centres down to just 10 at others.
"Studies suggest that low end of the scale is a risk factor for a child's development," said the lead researcher, Associate Professor Sheila Degotardi. "They are not getting the exposure to language that they need."
The researchers followed almost 60 children aged under two at their childcare centres, and recorded the number of words they heard from adults over three hours. A quarter of the children heard fewer than 11 words per minute.
Dr Degotardi said witnessing others having conversations was not enough for language development. The most effective kind of talk was frequent and direct, and went beyond instructions to discussion of things that interested the child.
"It builds their ability to engage in and take in conversation, so they become language users as well as language learners," said Dr Degotardi.
The study, which was the first to look at language in a long daycare context, found carers that used many words also had higher-quality interactions with the children. There was also a link between quality talk and highly-qualified staff.
"Quantity and quality seems to go together," Dr Degotardi said. "I would say it's probably not instinctive [behaviour from the carer]. We found that this was related to the qualification of the educator.
"In rooms where they had higher-qualified educators, the children we observed were getting more talk and higher-quality talk. To me that speaks to the importance of qualified staff in bringing up the capacity of all the educators."
New research suggests that differences in children's language development by age three can be significant for their learning future. "As the child gets older, it becomes harder for those children to catch up, and more and more expensive," said Dr Degotardi.
"With children that are already potentially at risk of having that gap, if you get them into high quality programs before the age of two, you can completely get rid of that gap," said Dr Degotardi.
Susan Reed, the acting director of Mia Mia childcare centre at Macquarie Park and a qualified teacher, has been working with kids for three decades. She talks to babies about what they're doing and what their next activity will be.
"It's also about asking children questions," she said. "You'll say something to them, and they'll say something back. They do listen and they can understand even though they might not have the verbal skills themselves."
Requirements for qualified teachers at child care centres vary depending on size, but a long daycare centre with between 25 and 59 students must have one in attendance for six hours per day.