Child Language Acquisition
Research and case
studies
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There have been many studies carried
out on young children to test various
theories about how they acquire
language.
Many of these are adapted from William O’Grady’s How Children
Learn Language (London: Cambridge University Press, 2005)
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Words and meanings

Describe in one word
what you see in each of
the images here.
Now try to
describe in two
words what you
see in each of the
images.
© John Hurd 2006
…
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‘Whole object assumption’

You probably came up with single nouns like lady,
woman, dog for the images first of all.

This relates to the ‘whole object assumption’ that
children make use of when confronted with new
things that they name.

You could have just as easily picked out a smaller
detail in each picture such as nose, hat, leg, face,
kettle or window, but you probably didn’t. Why not?
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‘Whole object assumption’

For children, a new word usually refers to a
whole object, not part of it or a quality the
object possesses.

When you were asked to use two words it’s
likely that you used a noun and a verb (lady
smiling or dog running) or a noun and a
modifier (lady happy or quick dog). There
are other alternatives of course…
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Words and meanings

Children tend to use nouns as their main word class
early on, and Katherine Nelson explored this in 1973
when she looked at patterns of children’s first 50
words.

There is some logic to this as most concrete nouns
fit into the four categories that Spelke noted:
cohesion, continuity, solidity, contact. Basically,
children like objects that are clearly defined in shape,
that don’t disappear, which are solid, and which don’t
have a life of their own (unless they’re animate –
animals or people).
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Words and meanings

Children also apply a couple of other
strategies: the type assumption and the
basic level assumption.

The type assumption prevents children
from underextending most new words. In
other words, if they are told that the new
thing they have seen is a dog, they don’t
assume that only that particular dog is a dog
and every other dog isn’t.
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© Geren W. Mortensen 2006
© David Poe 2007
After all, there
are lots of
different
dogs…
© 2005 Ian Grove-Stephensen
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Words and meanings

The basic level assumption prevents the child from
overextending meanings too far. So, once a child
has recognised what the noun ‘dog’ refers to, they
seem to understand that it also refers to things with
similar properties (appearance, behaviour, size).

So a dog shouldn’t be a horse, a cat or a ring-tailed
lemur… But it doesn’t always work that way, and the
mistakes children make seem to shed some light on
the processes they’re using to distinguish these
differences.
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Words and meanings
Developing categories and hierarchies is a part of
semantic understanding too.
Try these questions yourselves:
–
A pug is a kind of dog. Does a pug have to be an animal?
–
A BMW is a kind of car. Does a BMW have to be a vehicle?
–
Michael Jackson is a singer. Does Michael Jackson have to be a
kind of human?
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Words and meanings

You’ve probably been able to answer all these questions as
‘yes’. But faced with questions like this, four-year-olds only
score about 60%. Six-year-olds are better at about 90%.
Why?

This is down to the ‘mutual exclusivity assumption’: the belief
that an object cannot be two things at once.

In order to give a correct answer, the child needs to understand
that a dog is a kind of animal, a BMW is a car and part of the
wider class of vehicle. As children get older they start to
understand the hierarchical nature of naming categories.
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Subclasses of ‘Animal’
Fish
Dog
Pitbull
Terrier
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Poodle
Labrador
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Trout
Cod
Salmon
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Language productivity
Children are often extremely adept at
creating new words by applying the rules they
hear in use around them.

Try this test:
if a person who walks is a walker,
and a person who runs is a runner,
what would you call a person who
:
a) cycles; b) cooks; c) shoots?
…
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Language productivity

Your answers probably differ from those of young
children, because you will have heard the correct
versions in use more often. Children are likely to
have said ‘cycler’, ‘cooker’ and ‘shooter’.

But, you probably came up with ‘cyclist’, ‘chef/cook’
and ‘gunman/gangsta’.

When we add endings (bound morphemes) to words
to change their function we call it ‘derivation’. But we
also have other methods of creating new words.
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Language productivity
Conversion: when we change the word class of the
word but leave it in its original form:
–
–
–
–
to butter the bread (verb)
pass me the butter (noun)
kiss me (verb)
I gave her a kiss (noun)
Again, children often overuse these conversions.
Examples are: ‘I’ve jammed my bread’, ‘I’m scissoring
my picture’, ‘I’m pencilling a picture’.
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Language productivity

These errors are a good sign because they reveal to us the
processes at work in the child’s mind. Sadly, the English
language isn’t quite as logical as the child, and they have to
unlearn these errors.

This usually takes place over a period of time, as they hear the
correct words being used in context.

So they realise that we use –ist as well as –er for people who
do things (cyclist, typist), that you can’t just add a –y ending to
every noun to turn it into an adjective (‘It’s very nighty’, ‘This
room’s crowdy’) or that hammers don’t ham and doctors don’t
doct.
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Language productivity

Probably the most wellknown experiment into
how children use
endings to create new
words is the ‘wug test’
carried out in the 1950s
by Jean Berko.
Reproduced by permission from the Wug Test, © 2003 Jean Berko Gleason
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© Jean Berko Gleason 2003
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Language productivity

76% of 4-5 year olds got the correct –s ending
compared to 97% of 5-7 year olds.

Other nonsense words, such as heaf, lun, tor and
cra gave similar results, showing that when a plural
is a simple –s (or –z) sound children can apply the
rule.

They found it harder to add an –es ending (such as
in words like glasses, houses etc.).
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Overgeneralisation

Children tend to overgeneralise this rule and end up
creating incorrect forms such as mouses, childs,
sheeps and mans.

As we all know, the correct forms of these are
irregular: mice, children, sheep and men.
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Words and rules

Both the ‘wugs test’ and
wider research into how
children use endings like the
–ed past tense and –er/est
comparatives and
superlatives, reveal that
there is a U-shaped
development of correct use.
25
20
15
10
5

It starts high, drops off as
they start to apply the rule
and then improves as they
learn the exceptions to the
rule.
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Words and rules

Research by Roger Brown in the 1970s
seems to suggest that this pattern is due to
children using the correct form to begin with,
overgeneralising a rule and then learning
the exceptions to the rule.

By the end of roughly six months they will be
more accurate than they were at the
beginning.
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Words and rules

Gary Marcus researched past tense endings in 1992 and
came up with broadly similar points, but noted how few
errors children made (roughly 10% of past tense forms
were incorrect).

He proposed a model which suggested that children have
a choice when faced with past tense verbs: they can add
–ed or retrieve a special form.
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Words and rules

It explains why they sometimes say ‘runned’ or ‘seed’ but
also why they might do both and say ‘founded’ or
‘ranned’.

One is linked to a rule system, the other to memory. This
is developed by Steven Pinker in his books Words and
Rules (London: Weidenfeld & Nicholson, 1999) and The
Language Instinct (New York: William Morrow &
Company, 1994). Get reading if you want to do
Linguistics at uni!).
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