Dog or Dogs? When do children learn the difference?

Researchers at Macquarie University's Child Language Laboratory (in the Australian Hearing Hub) are one step closer to identifying a question that has long perplexed linguists and parents alike: when do children understand  that adding an –s to the end of a noun means 'more than one' (i.e., plural)?

Most languages provide just two options when talking about quantity: singular or plural.  Though some languages have more distinctions.

"For English, the actual number of things you are talking about doesn't really matter" explains Honours student Ben Davies. "There's either one, or more than one. Using plurals in speech is the first indication that children understand that meaning can be adapted by the minor modification of a word."

An awareness of these modifications indicates that a child is becoming more conscious of the connections between sound and meaning. By identifying the age at which children start to use plurals in their speech, we can better understand when they start to understand about the larger world.

"Kids know more about language than we think, earlier than we think," says Davies. "We know that most understand plurals by 24 months, but we know that many don't understand them at 18 months. So we're looking at children between 23 and 25 months to see when this development takes place."

Although children's speech provides an indication of this development, even quiet children may understand  plurals at this age. By asking children to "look at the cat" vs. "cats," and tracking their eye movements on the computer screen, Davies and colleagues are able to discern whether a child understands the difference, without them having to say a word.

"Parents often worry that their child isn't saying much and it's a sign that something is wrong," says Davies. "Even if your child is not talking much, they're probably listening."