My daughter thinks the moon is a ball…

We live in the middle of Brisbane City in a small Queenslander so my daughter’s first words so far have been quite ‘city-slickerish’.  Light (ight); fan, (ffff); ball (ba_); and shoes (sooz) are some of her earliest and best words so far.

So the ‘nature-lover’ in me was delighted to see her pointing up at the moon the other night.  Funnily enough, while she pointed to the moon, she unmistakably announced that it was a ‘ball’.  This mistake made me laugh but I also found it fascinating to reflect upon first words and how language develops.

Does my daughter really think the moon is a ball? No.

This is called ‘overextension’. ‘Overextension’ is a typical development error in early word learning as is defined as any use of a word incompatible with conventional adult reference, even if the child’s intent was sensible (Dada for father’s shoes).

There are three types of overextension and one of the most common types seen is the one my daughter has used:

Three Types of Overextension

1.  Similar Feature:  This is where your child refers to all items with a similar semantic feature as the same.  This is what my daughter is doing when she refers to the moon as a ball.  She has focussed on a key semantic feature of both objects being ‘round’.  Easily confused, wouldn’t you agree?!  These ‘overextensions’ are often an ‘inferred similarity’ rather than a conventional one.  My daughter knows that tea is hot and loves to hold her hand out and say “Oooo…ot (hot)” but she also says and does the same thing at the freezer!

2.  Category:  This is where your child will use one word to refer to all things in the same category.  For example, your child may point to any man and say “Daddy” (awkward!) or point to any four legged animal and say their version of the word dog.  Children use overextension as a way to group words into categories and develop concepts.

3. Relationship:  This is where a child attempts to comment on the relationship between two words; an item that is present and an item that is absent.  For example, your child saying ‘keys’ as they stand at the front door before you have even taken out your keys to unlock the door.  We have a dog that lives next door and even when he is not barking, she points to the house and says “oof” (woof).  The relationship overextensions are often thought to be the beginning of two word utterances or joining words together as the relationship between words is being explored.  For example, saying ‘bunny’ to the empty cot where the bunny normally is might be an attempt to say ‘bunny gone’.

Is Overextension Normal?

Yes it is normal to observe overextension in your child’s language as they try to enhance their language skills.

In fact, it is quite fascinating to learn that there is a striking consistency across children in the types of overextensions they make, with much of the errors being rule-governed and systematic.

How should we as parents respond to these ‘overextensions’?

One part of me thought, well she is right.  It is round like a ball.  A big ball high in the night sky, quite poetic really?!  What a clever chicken to put two and two together like that.    Should I really be correcting her or giving her high five for her effort?

However, the speech pathologist in me immediately knew to ‘recast’ her label by repeating the correct word instead of the mistake and saying “Oh, that’s the moon!  It’s a round moon.  Hello moon.  Goodnight Moon!”

According to research, many parents inadvertently promote the continuation of this developmental error ‘overextension’ by not providing this corrective feedback.  It may be because they don’t want to sound like an over critical parent or perhaps its simply an oversight.  However, it is important to realise that NOT correcting your child on these common mistakes won’t help them fix it.

Remember, your child just wants to communicate with you so, if you sound positive in your tone, they won’t mind if you model the correct word.  They might even thank you for it when they’re older and they know that the bright, white ball in the sky is in fact our moon!

Thanks for hearing our call,

Your Little Birdies xx


Rescorla, Leslie A. “Overextension in Early Language Development.” Journal of Child Language 7, no. 2 (1980): 321-335, doi: 10.1017/S0305000900002658.