Most children understand and speak language by the time they start school, usually at age five.
Research shows that, even in early infancy, babies show a preference for language over other sounds. Moreover, at a few weeks old, they also show a preference for the sounds of their mother tongue over the sounds of a foreign one. Indeed, after a few weeks, they can distinguish the sounds of their native language from other tongues.
Most babies speak their first words between their first birthday and eighteen months of age. The same child, by the age of four, is learning an average of ten words a day!
In the very early stages of learning, there is a difference between what a child hears, and what they can say. In "The Language Barrier," retired teacher Helen King tells the story of how her 15-month-old granddaughter learned to tell her father she loved him.
King prefaces her story by suggesting that a father's speech to their infant child tends to be more demanding than a mother's.
"Indeed, this was true of Erin's dad, who at a very early age, excited by her developing communication skills, said things to her like, 'Erin, say, I love daddy,' but, since Erin seemed to accept this in her stride, all was well.
"Of course, she didn't say, 'I love daddy' at that stage. But by amazing persistence on both their parts, she started getting somewhere. Her dad's teaching went like this.
"Erin, say 'I.'
"Erin responded, I.
"She had a bash at it.
"There was a bit of a hiccup because this game went on so long that soon, as soon as she said I, she followed with a triumphant, daddy.
King continues, "It seemed to me that language learning as such was not going on here, but both Erin and her dad, Damien, were enjoying a game, in which Erin was keen to please her dad. I didn't see how she could say, 'I love dad,' and mean it, since she didn't know the meaning of the word 'love' as yet.
"That is not to say she didn't love her dad, she most certainly did. But her dad was trying 'formal' teaching at too young an age and it just couldn't work. However, she was learning valuable interpersonal skills. She loved her dad, and recognized that if she could possibly complete the (to her) crazy task he was setting her, he would be pleased. So she did her best to please.
"An amusing bit of sign language developed from this. When Damien realized that the verbal communication wasn't getting there, he substituted a sign version. He would say 'I' and point to his eye, then 'love' accompanied by his hands clasped over his heart; finally with 'you,' he would point to Erin.
"She grasped this very quickly, and every morning as he left for work, she would go to the window and 'sign' her message to him.
"Though she has long since learned the words, they both use the same signs to the present day."