Modern parenting recommendations suggest that parents use as rarely as possible the word “NO”, and that instead of concentrating on the things that their children are not supposed to be doing, they ought to focus on what they should be doing instead.

But before choosing the parenting style that fits them best, the first question that new parents have is: when do the little ones start understanding the meaning of “NO”?

Many 9 month old parents tell us about the fact that their children understand, most of the times, the meaning of “NO”, but that instead more often than not they choose to ignore it.

Therefore, in order to better understand when and how our children start understanding the word “NO”, and why, at the same time, they choose to ignore us, their parents, we must understand at which age do children start understanding the concept of an interdiction.

The Haizea – Llevant chart, drawn based on studies performed on thousands of children, is quite helpful in determining the exact time that children start doing or saying certain things.

At the same time, it offers a minimal and maximal interval that shows us the moment when a child must start doing certain things and when it is already too late for them, which proves that the child is developmentally delayed.

In the Spanish medical system, paediatricians use the Haizea Llevant chart for children from 1 month to 60 months old (5 years). The chart has four columns, each for: social skills, language, the ability to manipulate and motor skills.

Haizea Llevant

The conclusions of this chart come from studies and observations of the developmental stages of children: when they start distinguishing their parents’ voices, catching objects, cooperating while being dressed etc.

The chart is very useful in diagnosing autism. The chart shows three different stages of development: the first one marks the moment when 50% of the children start doing something, the second one marks the moment around which 75% of the children do it, and the last interval marks the moment when 95% of the children have crossed that stage. The other 5% of the children require careful observation to determine whether a developmental delay (longer than usual) is taking place or whether autism can be taken into consideration.

According to this chart, a baby starts understanding the word “NO” at 8,3 months. The interdiction may simply be limited to “don’t touch” or “don’t eat that”. 50% of the children start understanding when their parents tell them “NO” at around this age.

Most babies (75%) understand the meaning of “NO” at 10,4 months old. And 95% of the children already know what “NO” means at 14,8 months old. By 15 months old, all children should be able to understand an interdiction.

At what age has your child started understanding the word “NO”?