Developmental language disorder
in deaf children:
Implications for teaching
Chloë MarshallChloë Marshall, PhD
Acknowledgements
Kathryn Mason Katherine Rowley Ros Herman
Joanna Atkinson Gary Morgan Bencie Woll
The context
External factors:
Quantity
Quality
of language input
Internal factors:
Individual differences in
language acquisition ability
Developmental language disorder (specific language impairment)
Diagnosed when
children have difficulty
acquiring their own
language for no
obvious reason.
Children have difficulty
understanding what
people say to them, and
struggle to articulate their
ideas and feelings.
On average, 2 children
in every class of 30 will
experience DLD severe
enough to hinder
academic progress.
Co-occurs with other difficulties, e.g. difficulties with literacy and mathematics.
Sign language development in deaf children
External factors:
Quantity
Quality
of sign language
input
Internal factors:
Can deaf children be
affected by DLD?
Speech and language therapists and teachers of the deaf report that they
encounter signing children with unexplained language impairments.
Research project at DCAL 2006-2011
Research questions:
Is it possible to identify DLD in deaf children who sign?
If so, how do their language difficulties compare to
those of hearing children learning spoken languages?
How prevalent is DLD in signers?
An obvious challenge
Deaf children who are learning to sign receive very
variable quantity and quality of sign language input.
If a deaf child is having difficulty acquiring sign language,
how can we be sure that this is due to an internal factor
(i.e. DLD) rather than external factors (i.e. poor
quantity/quality of input)?
Option 1: Focus on native signers
The paper reports the case of a deaf child
exposed to BSL from birth, who has significant
developmental deficits in the comprehension
and production of BSL grammar based on
formal assessment and linguistic analyses of
his sign communication in comparison with
age-matched unimpaired signers.
BUT NATIVE SIGNERS ARE RARE!
Option 2: Comparison with peers who also have non-native input
For non-native signers – we are seeking to identify a disorder on top of a delay.
3 stages of our research project
Questionnaire: To identify children with weaker-than-expected language skills
Standardised tests: Can children with a DLD-type profile be identified?
New, specially developed tests: To characterise the profile of DLD in greater detail
Stage 1: Questionnaire
Sent to over 60 deaf schools and specialist units
Children aged 8-14 years
50 children were referred to us
Stage 1: Questionnaire
Does the child have difficulty following instructions in BSL?
Does the child have difficulty understanding things signed to them?
Does the child frequently ask for signs to be repeated?
Does the child produce more gesture than BSL?
Does the child respond better when visual aids are used?
Does the child have poor memory for BSL information?
Does the child show hesitation when signing?
Does the child show frustration when signing?
IN
COMPARISON
TO
PEERS
Stage 2: Standardised assessments
26 children followed up
Based on methodology for identifying DLD in spoken
languages:
–British Ability Scales non-verbal tests
–BSL Receptive skills test (Herman et al, 1999)
–BSL Narrative skills test (Herman et al, 2004)
Stage 2: Results (Mason et al., 2010, BJDP)
BSL production test percentile
scores
Child BAS
z-score
BSL
Receptive
Test z-score Narrative
Content
Narrative
Structure
BSL
Grammar
Age
1 -0.6 0.3* 25* 50* 10* 13;11
2 -0.6 <-2.1 <10 <10 <10 7;04
3 -0.1 1.1* 10* 10* 25* 14;02
4 -0.9 -1.5* 10* 10* 10* 14;08
5 0.6 -2.1 <10 <10 <10 7;04
6 -0.7 0.1 25 10 50 11;00
7 -1.2 <-2.1 <10 10 25 5;10
8 -1.2 0.6 <10 <10 25 8;01
9 -0.6 -2.3 10 25 10 9;01
10 0.3 -1.5 <10 <10 <10 10;06
11 -0.5 <-2.1 <10 <10 <10 10;09
12 0.7 1.1 <25 10 <25 9;08
13 -1.0 -0.7 10 50 10 11;03
13 children
were considered
to have DLD
= 6.4% of the
population
sampled!
Stage 3: Specially-developed tests
Sentence repetition
Semantic fluency
Stage 3: Sentence repetition - rationale
A clinical marker for DLD in spoken language
E.g. The horse that the farmer pushed kicked him in the back. →
The horse that pushed the farmer kicked him in the back.
A measure of:
Linguistic knowledge – lexical, morphological, syntactic
Verbal short term memory
Has been investigated in many different languages and
included in many standardised language tests.
Stage 3: Sentence repetition - stimuli
Video removed
Stage 3: Sentence repetition – results (Marshall et al., 2015, LLD)
0
10
20
30
40
50
60
70
80
90
100
Total Spatial morph. Non-manual features Lexical content Sign order
mean%correct
Overall
exact
Spatial
morphology
Non-manual
features
Lexical
content
Sign order
*
*
(*) *
*
Control
N=13
DLD
N=13
Stage 3: Semantic fluency - rationale
Not a clinical marker for DLD in spoken languages.
However, some children with DLD do have word-finding difficulties
Semantic fluency is a quick test to administer and provides a lot of data
Stage 3: Semantic fluency - stimuli
Video removed
Stage 3: Semantic fluency – results (Marshall et al., 2013, JCL)
0
2
4
6
8
10
12
14
16
18
Total Correct Number of
clusters
Average
cluster size
Number of
switches
Control
SLI
Control
N=13
DLD
N=13
Numberofresponses
Stage 3: Semantic fluency – results (Marshall et al., 2013, JCL)
Some evidence of sign-finding
difficulties
(e.g. MOUSE IN WHEEL… YOU
KNOW! 7 s later: HAMSTER!)
0
1
2
3
4
5
6
7
8
9
1-15s 16-30s 31-45s 46-60s
Numberofresponses
*
→ Evidence that signers with DLD access signs more slowly
Control
N=13
DLD
N=13
Conclusions from this research project
DLD can be identified in signers,
but it is challenging to distinguish it from sign language delay.
DLD in sign has some of the same features as DLD in spoken languages,
despite the differences in modality:
Poor sentence repetition
Some word finding difficulties
What do we still need to know?
We need to better understand sign language development in signers without DLD.
What is the profile of signers with DLD
across development?
across languages?
What does bilingual-bimodal DLD look like in hearing signers?
How do we tease apart the effects of delay and disorder?
How does sign language proficiency relate to literacy, numeracy and other aspects
of learning?
Recent research from other groups: Quinto-Pozos et al., ASL
Case of a deaf native signer of American Sign Language (ASL) with DLD. School
records documented normal cognitive, but atypical language, development.
Average intelligence, intact visual perceptual skills, visuospatial skills, and motor
skills, yet challenges with some memory and sequential processing tasks.
Scores from ASL testing signalled language impairment and a marked difficulty
with fingerspelling.
Additionally, significant deficits in English vocabulary, spelling, reading
comprehension, reading fluency, and writing.
Recent research from other groups: Bogliotti et al., LSF
Mixed dominance
Lack of facial expression
Recent research from other groups: Bogliotti et al., LSF
Errors of reference and the
syntactic use of space
A result of all this work: The recognition of DLD in sign
It remains problematic to diagnose DLD in ORAL deaf children.
Old definition:
SLI is characterized by the inability to master
spoken and written language expression and
comprehension, despite normal nonverbal
intelligence, hearing acuity, and speech
motor skills, and no overt physical disability,
recognized syndrome, or other mitigating
medical factors known to cause language
disorders in children.
New definition (ICD-11):
DLD is characterized by persistent
difficulties in the acquisition,
understanding, production or use of
language (spoken or signed), that arise
during the developmental period,
typically during early childhood, and
cause significant limitations in the
individual’s ability to communicate.
Implications for teaching
Awareness that a child with poorer-than-expected sign language skills
might be affected by DLD, and not just by impoverished sign language
input.
Such a child might also have concomitant difficulties in literacy.
This child might benefit from particular types of support.
@DOTdeaf
Prof. Ros Herman and Dr Joanne Hoskins
Exciting new ERASMUS+-funded study
Aim: To develop online training for deaf practitioners working
with signing deaf children with broad language difficulties.
Email: r.c.herman@city.ac.uk
Find out more
Marshall, C. & Morgan, G. (2016). Investigating sign language development,
delay, and disorder in deaf children. In M. Marschark & P. E. Spencer (Eds.),
The Oxford handbook of deaf studies in language (pp. 311-324). New York,
NY: Oxford University Press.
chloe.marshall@ucl.ac.uk
Marshall, C. & Morgan, G. (2016). Specific language impairment in deaf and
hard-of-hearing children who use a signed language, website Raising and
Educating Deaf Children: Foundations for Policy, Practice, and Outcomes