Uses a word they know for all individual people or objects in a category, e.g. calls all men 'daddy'

Your toddler has been learning lots of early words and they most likely will have linked to family members, routines or objects that are familiar to them. They may be uttering two words phrases such as ‘uh oh’ or ‘bye bye’ and they may have started using a wider variety of words such as adjectives, nouns and some verbs.  

Overextension of words 

There has been a lot of research into the overextension of words in early language development. Overextension means using one word for a greater variety of objects than is typical in adult usage, for example your toddler may see a cat, they are told that it is a cat so they think all four-legged animals are a cat. 

Even though your toddler has gained a wider variety of words, they are still making sense of how to use them. This is a natural stage for toddlers to learn that a cat is a cat, not a dog, and that a shoe is a shoe, not a boot. [1] They are learning how to use one word to describe one thing, [2] not only that, but also that when they are learning about a shoe, the shoe can be their shoe, a friend’s shoe, a shoe belonging to a family member, or someone walking past on the street [3] 

When we think about the number of different words a toddler hears and tries to make sense of, the number of words is enormous. Let’s take a clock as one simple object. A clock could be a watch, a grandfather clock, a timer, a digital image on a screen, a wall clock, a tabletop clock, a novelty clock or a sand timer. That is a lot of words for one classification of the object. Then, when we think about different items that display numbers, that could be a clock, but aren’t, like a weighing scale, telephone, washing machine dials etc. your toddler has much to work out. 

Whilst your toddler is attempting to connect various words to objects, they frequently make errors. They are attempting to decipher the meanings of words [4], using the limited knowledge and understanding that have gained so far in life. Researchers have identified a few possibilities as to why children might occasionally use one word to describe multiple objects or individuals:

1) Category errors 

Your toddler is learning a wealth of new vocabulary and they are processing what all these words mean. They have a bit of knowledge as to what the object could be and are able to classify it into their own category, let's take a peach as an example. They may call a peach an apple. The mistake could happen as they might understand that like the apple, the peach is a type of food, plus there is a link between colour, shape, size. When they look at a peach they are working hard to try and classify this object. [3] 

2) They haven't yet learned the word 

Toddlers have some way to go before they have extended their vocabulary to that of an older child, never mind an adult. Sometimes they haven’t seen an object and cannot know what it is they are trying to describe. It is at times like these that researchers think they fall back on their knowledge of category and choose a word which they things suits best [3] 

3) Memory 

Toddlers might not sometimes be able to access the word they are searching for and come up with the closest thing. They may choose a word that sounds like the word they are thinking of, or they will say a word that matches the aesthetics of the word they are trying to retrieve [3] 

4) All of the above 

Other researchers put forward that all three of the above ideas come under one umbrella of identifying a word, meaning toddlers will use a combination of category, a gap in knowledge and memory for their overextension mistakes.  

What next? 

Toddlers can be helped along with their understanding of vocabulary when adults support them to form their knowledge of vocabulary with more information. If a toddler were to call a rabbit, a squirrel due to the fact they were both grey, fluffy, had four legs and sticky up ears. An adult could assist in the classifying of both animals by saying something like, ‘squirrels have very long fluffy tails, they live outside, love to climb trees and bury nuts. Rabbits are usually much bigger and can live outside or inside, people keep them as pets in hutches.’ 

Your toddler will begin to make more sense of the world, objects and language. Their ability to group objects into smaller categories will grow as they gain more experience with a variety of objects and people. They will start to draw upon their memory and think more widely about what they can see. This can take some time, due to the number of definitions, words and objects. 

References: 

[1] S. Durrant (2020). Blog: Have you ever wondered how you learned to talk? 10/02/2020. Available online at: Have you ever wondered how you learned to talk? | LuCiD 

[2] Gotzke, C. & Sample Gosse, H. (2007). Parent Narrative: Language 13 - 24 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 8. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development 

[3] M. Saxton (2017). Child Language Acquisition and Development 2nd Edition. Sage Publications Ltd. 

[4] D. Crystal (2005) How Language Works How Babies Babble, Words Change Meaning and Languages Live or Die. Penguin Books.