Within this essay I will compare the
acquisition of language in deaf children to hearing children, by looking at the
innateness of babbling, nurturing aspect of Child Directed Speech (henceforth
CDS) and critical period hypothesis in the case of Chelsea. I aim to draw the
conclusion that language is neither innate nor ?? rather a balance of the two.
The act of babbling is something which strongly supports the innatism argument,
as it is a universal behaviour (Oller and Eilers, 1988).
Lenneberg et al (1965, as cited in Gilbert 2002) uncovered that all children
babble, and the babbling begins around the same age for all children irrelevant
of their hearing capacity. The babbling in deaf children however was reportedly
more monotonous and less varying in pitch than hearing infants. Further
research revealed that deaf children stop babbling earlier, and either do not
go on to use a vocal language or do so with deviant language.
It is thought that this is because the deaf infant has no auditory feedback
, which I believe is highly significant to effective to language acquisition.
The evidence of deaf children babbling in early life would suggest an innate
predisposition to acquire language. However, I would argue that in the case of
deaf children, where babbling stops, and no further language is acquired, this
predisposition is not fulfilled due to lack of environmental input. The above
research provides evidence to suggest that in fact, children who do not receive
sufficient external input (deaf children who lack auditory input), do not go on
to achieve an equal verbal fluency as those who do (hearing children with
auditory input.) I would argue therefore that this is contrary to Chomsky since
whilst a predisposition to learn language may be present, it’s actual
acquisition is not innate but environmentally nurtured.
The nurturing of language acquisition can be found in the form of Child
directed speech. In
hearing children, CDS is an integral aspect of language acquisition, it is used
by the caregiver to encourage the infant to engage in conversation. It
features, elongation and repetition of words, simplification of lexis, greater
range of pitch, which is predominantly higher and slowing down overall speech.
A study by Karzon (1985 as cited in Altmann 2002)
researched the response of 1- to 4-month olds to two different words “marana”
and “malana”, when these words were read to the infant in CDS (higher pitch and
exaggerating the middle syllable, ra or la) the children were able to
distinguish the difference between the sounds, this was noted by the change in sucking
pattern. However when read the words in adult directed speech, the child showed
no recognition of the difference. The results of this research shows to me that
the use of CDS in communicating with children can be hugely beneficial to their
phonemic and lexical development. Enabling them to establish difference in
sound will eventually provide them the skill to distinguish between words and
their meanings, for example ‘a bat’ is an animal an ‘to pat’ is an action.
Deaf children in deaf households would have no exposure to this kind of
learning, which leads us to question: how do they gather understanding of
language without the CDS input?
Following a study conducted in Japan (Masataka 1996), it was revealed through
observing via filming mothers sign an identical script to their 6-month old
child and then a deaf adult, that they signed at a slower tempo when
communicating with the infant, repeated signs and exaggerated their hand
Mothers of deaf
children show intonation, and pitch through use of facial expressions, making
them more simplified and exaggerated to clearly convey emphasis, for instance:
raising eyebrows at the end of a sentence to show higher pitch, forming a
question (Boys Town National Research Hospital, 2018).
In the ‘The Language Instinct’ innatist
Steven Pinker (1994) claims that children can acquire language without the
input of CDS as people who move country in adolescence can still learn most of
their new language when no CDS would be heard. I
would suggest that as Pinker infers the person can only understand “much” of
the language and not all, the use of CDS
in language acquisition with hearing and non-hearing infants, heavily implies
that it has a purpose for both audio and visual learning. The use of CDS in
both instances, highlights to me its importance in development of a language.
The case of Chelsea can inform us on language acquisition of a deaf language
learner under abnormal circumstances. Research into Chelsea conducted by
Glusker et al (1990) and Curtiss (1995) tells us
that she was born into a family of “normal intelligence” which had no previous
cases of developmental disabilities. Chelsea developed normally other than her
speech. Her mother believed her to be deaf due to her lack of response to
anything except incredibly loud sounds, she was tested but the results appeared
to show her as a hearing child. At 32 years of age Chelsea was later diagnosed
as hard of hearing after testing revealed she suffered from “profound hearing
loss”. Following diagnosis, she was given hearing aids and underwent an intense
programme of language and cognitive training which continued over 30 years.
In terms of her lexical development, Chelsea was unable to demonstrate her
knowledge of vocabulary consistently throughout testing. When asked to name
contents of a picture Chelsea consistently performed badly on these tests
irrelevant of if she recalled the word from her own memory or if she was given
a word to allocate to a picture (Curtiss and Yamada 1981). However, in tasks regarding
categories (e.g. animals Semel and Wiig 1980) where she was unprompted,
Chelsea’s vocabulary was far more extensive, her lists of words contained
unusual items (“Possum, Heron”) and items related to one another (“Chipmunk –
Squirrel”) these were recorded in 1989, 9 years after discovery, there was
found to be no change in these results when recall was recorded again in 1995
Grammatically Chelsea’s development was minimal and virtually non existent. Her
concept of verbs in terms of the theta-argument (which informs us of how many
and what types of noun phrases are required by a verb NEED A SOURCE) leads her
to form incorrectly structured utterances.
Her understanding of semantics was discovered to be impaired, she was given
Jackson’s (1985 as cited in Schütze and Stockall 2014) Semantic judgement test,
where the participant is told to decide if a sentence was “silly” or sensible.
The test has been successful with normally developing children around the ages
of four to seven.
As seen by the table above, Chelsea had little understanding of semantics and
it took her around 6 years to gather a small understanding of the traits of the
item in the test, like knowing that a house cannot be sad and a door cannot
eat. Whilst this took time it does show some development in her comprehension,
although in terms of syntactical categories, Chelsea’s utterances remained
hugely deviant, composing sentences like “Fiving the
boy looking five” which means “The boy looks
five years old”. Chelsea has not only deviated from a typical SVO order
but has tried to make ‘five’ a verb, moving it and ‘looks’ into the present ??
by adding -ing, and shortening the adjective phrase to five as opposed to five
The language acquisition of Chelsea clearly shows that theory of the critical
period holds some weight, as she did not reach a complete fluency of language
which a ‘normal’ person would. I would argue however, that the age of first
language acquisition is not the only reason for deviant language, Chelsea was
never tested as a child and we do not know for certain that had she have been
diagnosed and given hearing aids at a younger age, she would have achieved a
higher level of language comprehension and formation. Moreover, her grammar is
completely deviant and compares to no known language, yet her lexical
development is relatively equal to that of a child who began language
acquisition early on.
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Glusker P., Curtiss, S., Dronkers, N., Howard, F., Moilanen, N., Neville, H.,
Reisman, N., Ervin-Tripp, S., and Yancey, V. (1990) Primary language acquisition in a deaf adult: The Chelsea Project.
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As cited in:
Schütze, C. T. and Stockall, L. (2014) The Case of Chelsea: The effects of late
age at exposure to language on language performace and evidence for the
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