You might expect children to have the same level of language as adults.
But there are some things they might be less likely to say.
It’s one of the reasons why children’s language is so difficult to understand, and why you might not have a clue what they’re saying unless you see them make a sound.
“We are taught to be in control of our language.
You’re not going to be able to tell that they’re in control,” says Dr Sarah Kavanagh from the University of Bristol.
But it’s not always so simple.
“It’s possible that when we see an infant talking to a parent, it’s actually just a communication between a parent and their infant,” she says.
Dr Kavanah has developed an algorithm that helps teachers to make inferences about what is going on in the child’s head.
If there’s a clear difference between the baby’s speech and what they are saying, then it’s a sign that the child is being told in infant speech.
“The only way we can really tell if an infant is being directed is if they’re being told to say something and they’re not,” she explains.
“So the question we really want to answer is, is this baby being directed?
And if they are, what are they saying?
And then the answer is: it’s very difficult to tell.”
Infant speech is often very quiet Dr Kavannagh says the more difficult it is to tell what a baby is actually saying, the more likely it is that they are being directed.
“You’re just really going to have to be patient to try and tell them,” she adds.
“When we talk about the baby language, it means a lot more to us than what is actually spoken.”
This means that if you’re a parent with a young child, it may be easier to recognise certain patterns than other babies.
But Dr Kvanagh says it’s still not quite as simple as it might seem.
“In general, the language children use is quite different from what their parents might say,” she tells BBC Radio 4’s Today programme.
“They are using a much different set of rules to what parents are used to.”
Infants’ language is often quieter and less emotional A study published in December 2016 in the journal Cognition by researchers at the University at Buffalo in New York looked at the behaviour of infants in the USA and Europe.
They found that babies aged between six months and six years had lower language processing and more emotion-processing in their brains.
This was partly because babies were more exposed to their mothers’ emotional language, such as crying or laughing.
“This is what is really important in developing a child’s language because we want to help the child understand their environment, their environment is not always the same as the parents,” says Professor Rui Sperling from the university’s Department of Psychology.
But babies are also learning to speak more easily than adults.
This means their speech is usually more complex and has a wider range of sounds.
“Baby language is more complex, and it’s probably a more expressive language,” Dr Kwanagh says.
“As a parent you want to be very aware of how your baby is using it.”
Inflammation can cause the baby to make a mistake A study conducted in 2007 by researchers from the National Institute of Mental Health in New Zealand, found that when infants were exposed to inflammatory conditions, their language was also impaired.
In this study, researchers compared infants’ ability to make the sounds of a crying baby and a normal infant.
They discovered that babies exposed to inflammation were much more likely to make mistakes.
“If a baby has inflammation in their brain, it can lead to this problem in their language because they have difficulty hearing,” Dr Sperring explains.
So what can you do if you think your child may be struggling to understand your language?
“You can just be very careful with what you’re saying, and really try and make sure that the baby understands what you are saying,” Dr Tod Matson from the American Academy of Pediatrics explains.
And don’t just take their word for it.
Ask your child’s teacher.
“There’s a huge difference between how a child thinks about the language they’re using and the language a child would use,” says Prof Sperding.
“But they’ll always be able get it correct.”
What you can do If you think you may be hearing the words of your child incorrectly, there are a few things you can try.
Read the baby talk: Infant talk is often more emotional and often features more vocalisation.
But in most cases it will have fewer sounds and may be spoken in a calm, conversational tone.
The most important thing is to let your child understand what they want to hear.
“To be honest with them, they’ll never say ‘I like your voice’ or ‘I want you to say it to me’.” Dr Saffron is now a psychologist with the British