The document summarizes a study comparing the language and phonological skills of children at high risk of reading difficulties due to speech difficulties and those with a family history of dyslexia. The two at-risk groups performed similarly, with average vocabulary but poor speech processing, phonological learning, awareness, and reading development. Both groups showed deficits in developing phonological representations, suggesting similar antecedents of reading difficulty.

1. Language and phonological skills in children
at high risk of reading di⁄culties
Julia M. Carroll and Margaret J. Snowling
University of York, UK
Background: Dyslexia is now generally acknowledged to involve difficulties in phonological processing.
However, the links between reading difficulties and speech difficulties remain unclear. Method: In the
present study, 17 children with speech difficulties between the ages of four and six were compared to
children with a family history of dyslexia and normally developing controls on phonological processing,
phonological learning, phonological awareness and literacy tasks. Results: The two groups of children
at risk of reading difficulties showed very similar patterns of impairment, with average vocabulary but
poor input and output speech processing, phonological learning, phonological awareness and reading
development. Conclusions: It is concluded that the antecedents of reading difficulty are similar in
these two groups of children, with both groups showing deficits in the development of phonological
representations. Keywords: Diagnosis, dyslexia, high risk studies, learning, phonological processing.
It is widely accepted that learning to read depends on
phonological skills and the corollary of this is that
children who have phonological difficulties are at
risk of reading problems. The group of children
whose phonological deficits have attracted most re-
search attention are those with dyslexia; these chil-
dren’s deficits encompass problems of phonological
awareness, verbal short-term memory and rapid
automatised naming (Snowling, 2000a). Another
group of children who are vulnerable to reading dif-
ficulties are children with problems of expressive
phonology. These children have phonological
impairments that can be observed in speech output
processes (Dodd, 1995; Stackhouse & Snowling,
1992). The extent to which their reading problems
can be traced to deficits in phonological skills, rather
than to broader language impairments that fre-
quently accompany these, is not yet fully under-
stood.
Bishop and Adams (1990) followed the progress of
a group of children who had had pre-school speech
and language impairments at the age of 8 years. The
literacy skills of those who had had isolated phono-
logical impairments affecting expressive phonology
were significantly better than those of children with
language difficulties. Similar results were reported
by Catts (1991) who found that children assessed in
kindergarten as having speech impairments in the
absence of language problems showed comparable
reading levels to controls one year later in first grade.
In contrast, children with speech and additional
language impairments showed significantly worse
performance. Similar findings were reported by Levi,
Capozzi, Fabrizi, and Sechi (1982) and Nathan,
Stackhouse, Goulandris, and Snowling (in press).
Both of these studies compared the reading skills of
speech-impaired children with and without addi-
tional language problems. While both groups were
delayed in literacy development, the children with
additional language difficulties were more signific-
antly impaired. These studies therefore suggest it is
language, rather than speech, difficulties that are
the main precursors of reading problems. However,
it should be noted that the children classified as
Ôspeech and language impairedÕ in these studies were
more severely impaired in their speech as well as
their language than the speech-only impaired group.
It is therefore difficult to disentangle the effects of
poor speech from those of poor language.
Bird, Bishop, and Freeman (1995) conducted a
study of speech-impaired children that avoided this
methodological difficulty by comparing subgroups of
children with and without language impairment that
had equivalent levels of speech difficulty at the
beginning of the study when they were aged five to
six years old. When these children were followed up
one and two years later, they showed deficits relative
to controls matched for non-verbal IQ in reading,
spelling and phonological awareness. These deficits
were irrespective of whether children had additional
language difficulties.
The close similarity between the reading and
phonological awareness difficulties observed among
children with dyslexia and those with speech diffi-
culties is such that it has been suggested that the
two disorders lie on a continuum (Stackhouse &
Wells, 1997; Snowling, 2000b) that has phonological
processing difficulties at its core (cf. Stanovich &
Siegal, 1994). In similar vein, Bishop and Adams
(1990) proposed the Ôcritical age hypothesisÕ, which
states that the extent to which a child is vulnerable
to reading failure depends upon the status of their
phonological processing skills at the stage when
these are required for learning to read.
A second issue that is not yet resolved regarding
the risk of reading difficulties among children with
Journal of Child Psychology and Psychiatry 45:3 (2004), pp 631–640
Ó Association for Child Psychology and Psychiatry, 2004.
Published by Blackwell Publishing, 9600 Garsington Road, Oxford OX4 2DQ, UK and 350 Main Street, Malden, MA 02148, USA

2. speech impairments relates to the nature of their
phonological impairments. An integrating theory is
that reading difficulties can be traced to poorly spe-
cified phonological representations (Fowler, 1991;
Metsala, 1997; Ramus, 2001; Swan & Goswami,
1997; Snowling & Hulme, 1994; Snowling, Bishop, &
Stothard, 2000). However, this hypothesis leaves
open the question of the extent of involvement of
speech input (perception) and speech output (pro-
duction) processes. Studies that have examined
speech perception and spoken word identification in
dyslexic readers have produced equivocal findings
(Brady, 1997; Griffiths & Snowling, 2001; McBride-
Chang, 1996; Metsala, 1997; Pennington & Lefly,
2001).
Joanisse, Manis, Keating, and Seidenberg (2000)
have suggested that variability in speech perception
in dyslexia is associated with individual differences
in oral language skill. Thus, perceptual problems
appear to be more common among children with
dyslexia who have concomitant language impair-
ments.
Studies that have examined the speech production
abilities of children with dyslexia are comparatively
rare (cf. Snowling, Hulme, Wells, & Goulandris,
1992). However, evidence from prospective studies of
dyslexia among children from families at genetic risk
of the disorder suggests that such difficulties are
apparent during the pre-school years (Scarborough,
1990). Furthermore, school-age children with dys-
lexia have difficulties on nonword repetition tasks
that tap output phonological processes (Snowling,
1981; Snowling, Goulandris, Bowlby, & Howell,
1986). Indeed, Kamhi and Catts (1986) reported that
performance on a test requiring the repetition of
multisyllabic nonwords was as poor for reading-
impaired children as for children with primary oral
language impairments. Adding to the evidence
implicating speech production deficits in reading
failure, Leitao, Hogben, and Fletcher (1997) showed
that speech-impaired children who showed a pattern
of ÔdeviantÕ speech errors were poorer on tests of
phonological awareness than speech-impaired chil-
dren whose phonological errors could be described
as delayed, i.e., like those of younger children.
In short, there is reason to believe that there are
continuities between oral and written language dif-
ficulties. However, the hypothesis that developmen-
tal speech difficulties presage dyslexia is simplistic.
It seems that the risk of dyslexia is increased among
children with speech problems but the risk is mod-
erated both by the age at which the speech problems
resolve and the nature (and severity) of the speech
difficulty. Following on from this, Stackhouse and
colleagues (Stackhouse, 2000; Nathan et al., in
press) argued that children with speech problems
are at risk of literacy problems if they have meta-
phonological difficulties, particularly deficits in
phoneme awareness. The present study explored the
relationship between dyslexia and speech difficulties
by assessing the emergent reading-related skills of
children with speech difficulties who were receiving
speech and language therapy at the time of the study
and comparing them with those of children at family
risk of reading difficulties by virtue of having an older
sibling or parent who was dyslexic.
There are now a significant number of studies that
have shown the risk of dyslexia is heightened among
first degree relatives of people with dyslexia, with
between 32% and 65% of the offspring of dyslexic
parents going on to have reading problems (Elbro,
Borstrom, & Peterson, 1998; Pennington & Lefly,
2001; Scarborough, 1990). Taken together, the
findings of these family studies present a fairly
unitary picture; the vocabulary skills of children at
high risk of dyslexia are poorer than those of controls
during the pre-school years (Gallagher, Frith, &
Snowling, 2000) and their phonological awareness
and letter knowledge are poorly developed at the
ages of 4 and 5 years (Gallagher et al., 2000; Penn-
ington & Lefly, 2001; Scarborough, 1990). Moreover,
there is some evidence that children at family risk of
dyslexia show inaccurate articulation of known
words (Scarborough, 1990; Elbro et al., 1998).
In order to provide a comprehensive assessment of
the phonological skills of the two experimental
groups, we used tests of phonological learning and
phonological awareness as well as assessing basic
phonological processes. Given that we selected one
group to have speech problems, we predicted that
their performance would be less good than that of the
children at family risk of dyslexia on a test of output
phonological skills, namely nonword repetition.
However, in line with previous findings (e.g., Kamhi
& Catts, 1986; Gallagher et al., 2000), we expected
both groups to perform less well than typically
developing children. We included one test of input
phonological processing, namely a task in which
children had to decide whether a word that they
heard was correctly pronounced or not. This task
has not, to our knowledge, been used with children
with reading disabilities; however, spoken word
identification skills have tended to be associated
with vocabulary development (Walley, 1993; Metsala
& Walley, 1998) and to this extent we predicted that
differences between the high-risk participants and
controls would turn on their verbal abilities.
To assess phonological awareness, we included
tests tapping matching phonological segments at the
level of syllables, rimes and phonemes. We expected
that both high-risk groups would show phonological
awareness deficits relative to controls but, in line
with the developmental progression of phonological
skills, we predicted that these would be more
marked for small units (phonemes) than for the lar-
ger units of syllables and rimes.
We also wished to investigate the ability of the
children to learn new words. One of the strongest
early predictors of reading ability is letter-knowledge
(e.g., Adams, 1990; Muter, Hulme, Snowling, &
632 Julia M. Carroll and Margaret J. Snowling

3. Taylor, 1998) and children at high risk of dyslexia
show poor letter knowledge at school entry (Scar-
borough, 1990). To learn a letter’s name or sound
requires the association of a visual symbol with a
novel phonological form. It is conceivable, therefore,
that differences in phonological learning between
children with dyslexia and normally developing
children could account for differences in their con-
solidated knowledge of letters. This hypothesis is
particularly appealing in view of the reported diffi-
culties that dyslexic children have in visual–verbal
paired associate learning (Vellutino, Scanlon, &
Spearing, 1995; Vellutino, Steger, Harding, & Phil-
lips, 1975). A quite separate body of research shows
that children with specific language impairments are
slower than children with normal language devel-
opment to acquire the meanings of new words in
tasks of Quick Incidental Learning Tasks (QUIL;
Oetting, Rice, & Swank, 1995; Rice, Oetting, Mar-
quis, & Bode, 1994). Although the children studied
by these investigators have typically had receptive
language impairments, it is at least conceivable that
phonological problems contribute to the problem
they have in storing new word forms. We therefore
predicted that both groups of high-risk children
would acquire fewer novel phonological forms
(words) in an incidental learning task than controls
at low risk of reading difficulties.
In summary, we tested the differences between
children with family risk of dyslexia and children
with speech difficulties in four different domains;
literacy, phonological awareness, phonological pro-
cessing and phonological learning. It is hypothesised
that the children selected for speech difficulties will
show weak phonological processing and phonolo-
gical awareness, as found by Bird et al. (1995). It is
also hypothesised that the children with a family risk
of dyslexia will show weak emergent literacy and
phonological awareness, as described by Gallagher
et al. (2002). In line with the phonological represen-
tations hypothesis, it is further predicted that both
groups of high-risk children will show weak phono-
logical learning (Snowling, Gallagher, & Frith, 2003).
Method
Participants
Fifty-one children aged between 3;11 years and 6;06
years took part in the study. The children comprised
three groups of matched triplets; the family-risk group
comprised 17 children (6 girls and 11 boys) who had a
parent or sibling with diagnosed dyslexia. Each of
these children was matched to a child from the
speech-impaired group and a child from the control
group on the basis of age and, as far as possible,
educational experience. The speech-impaired group
comprised 17 children (6 girls and 11 boys) who were
currently undergoing speech therapy. They were
selected by their speech therapists as having signific-
antly delayed speech, but average language develop-
ment. None of the children in this group had a family
history of dyslexia. The control group comprised 17
children (9 girls and 8 boys) who were free of speech
difficulties and reported no family history of reading
problems. Ten of the children in each group were from
state schools or nurseries. Seven of the family-risk
and control children were from independent schools,
and they were matched to four speech-impaired chil-
dren in independent education and three speech-
impaired children who were in state education but
having speech therapy from a private speech therap-
ist. Two of the children in the family-risk group were
receiving regular speech therapy. Children from the
family-risk and speech-impaired groups were tested
either in their homes or in clinics, usually in one or
two sessions. The children who acted as controls were
tested in their schools. The three groups had equi-
valent ages and vocabulary scores, which are shown,
together with the descriptive statistics for the other
variables, in Table 1.
Tests and materials
Language skills. Receptive vocabulary: Vocabulary
knowledge was measured using the British Picture
Vocabulary Scale (long version; Dunn, Dunn, Whetton,
& Pintilie, 1982). In this test, the child hears a word and
is asked to point out which picture the word depicts
from a set of four alternatives. The test continues until
the child makes six errors in eight items.
Table 1 Performance of family-risk, speech-impaired and control groups on the background measures and experimental tasks
Control Family risk Speech impaired
Age1
62.53 (9.68) 62.71 (9.86) 62.76 (10.07)
Vocabulary2
102.06 (8.53) 104.35 (11.20) 102.59 (13.00)
Expressive phonology3
91.89 (5.55) 81.23 (17.38) 62.29 (21.65)
Nonword repetition4
17.76 (2.63) 12.47 (4.95) 6.18 (4.49)
Mispronunciation detection 5
20.12 (2.67) 17.71 (3.90) 17.18 (4.14)
Phonological learning Recognition6
4.94 (1.24) 3.69 (1.85) 3.87 (1.36)
Phonological learning Recall6
1.43 (1.16) .50 (.65) .79 (.97)
Syllable matching7
13.12 (2.74) 12.41 (2.74) 11.24 (2.88)
Rime matching7
14.06 (2.44) 11.76 (3.65) 12.18 (3.86)
Phoneme matching7
13.12 (3.44) 11.88 (3.18) 10.13 (3.93)
Letter-sound knowledge8
18.88 (8.26) 18.71 (7.99) 14.41 (9.38)
Word recognition9
21.18 (17.10) 15.35 (13.94) 12.88 (13.93)
Notes: 1
months; 2
standard score; 3
% consonants correct; 4
Max ¼ 24; 5
Max ¼ 23; 6
Max ¼ 6; 7
Max ¼ 16; 8
Max. ¼ 26; 9
Max. ¼ 42.
Children at risk of reading difficulties 633

4. Phonological processing. Mispronunciation detection
(input phonology): In this task, the children were intro-
duced to a puppet that looked like Cookie Monster, from
Sesame Street. They were told that he was a baby
monster, who was just learning to talk. Sometimes he
said words right, but sometimes he said words wrong.
They were asked to listen carefully to what he said and
to tell him if he had said each word right or wrong.
Three practice items were given, with full feedback, and
a brief discussion of what the monster said, and what
he was trying to say, to make sure that the child
understood the task. The child then heard 23 words.
The words varied as to whether they were one-syllable
words or three-syllable words, and whether they had a
high or low age of acquisition. Eight of the 23 words
were correctly pronounced, and 15 were mispro-
nounced by substituting a single consonant phoneme.
Seven of these had their initial consonant mispro-
nounced (e.g., nuck for duck), and eight had a later
consonant mispronounced, either a medial consonant
(e.g., golilla for gorilla) in the case of the three-syllable
words or a final consonant (e.g., moush for mouse) in
the case of the one-syllable words.
Expressive phonology: In order to provide a measure
of the quality of each child’s articulation, his or her
responses to items on a confrontation naming task were
transcribed and a score representing the percentage of
consonants correct was derived (Shriberg & Kwiat-
kowski, 1982). The naming task comprised 21 pictures
of objects, the names of which had two and three syl-
lables with an observed age of acquisition of less than
four years. Seven of the words had an unstressed initial
syllable (e.g., gorilla), seven of them contained con-
sonant clusters (e.g., screwdriver) and seven of them
contained vowels as a full syllable (e.g., caterpillar).
Eleven of the words were also used in the mis-
pronunciation detection task. If a child failed to name
an item correctly they were given a semantic clue. If
they were still unable to name the picture, they were
told the correct name and re-tested on that item at the
end of the test. If the child still failed to produce that
item then it was assumed that the child did not know
that word and it was removed in the calculation of that
child’s total score.
Nonword repetition (output phonology): The children
were also given a nonword repetition task. Nonword
repetition is a task that in the school years consistently
distinguishes normally developing children from chil-
dren with language difficulties (Bishop, North, & Don-
lan, 1996). The test consisted of 12 two- and three-
syllable nonwords. Eight of these words had primary
stress on the initial syllable, e.g., flitherty, 4 of them had
primary stress on the second syllable, e.g., bemure. Two
points were given for every nonword correctly repeated,
and one point for each nonword pronounced with a
single phoneme error (an inserted, deleted or substi-
tuted phoneme).
Phonological learning. To assess phonological learn-
ing skills, the child was presented with 6 new words to
learn, embedded in the narrative of a storybook, The
Gruffalo (Donaldson & Scheffler, 1999). This story de-
scribes a monster called a Gruffalo, and then follows a
mouse as he searches for the Gruffalo in the forest. Six
words were selected from the description of the Gruffalo
to be the target words. Four of these were changed from
the words in the published story into words not likely to
be known by young children. Real words were used for
ethical reasons, and pre-testing showed that the words
were not generally known to the children. The words
consisted of three nouns and three adjectives; wart,
talons, tusk, lilac, amber, gnarly. ÔTuskÕ and ÔwartÕ were
words present in the original story, but ÔtalonsÕ, ÔlilacÕ,
ÔamberÕ and ÔgnarlyÕ replaced ÔclawsÕ, ÔpurpleÕ, ÔorangeÕ
and ÔknobblyÕ, respectively.
At the beginning of the experiment, the children were
shown a picture of the Gruffalo from the book and were
asked to point to his ears and to his tail as practice
items to make sure that they understood the task. Then
they were asked if they could point to each of the target
parts of the picture in turn. For instance, they were
asked ÔCan you see his talons? Where do you think his
talons are?Õ The children were given corrective feed-
back. Scores on this part of the test formed the pre-test
score. The story was then read to the child with him or
her looking at the pictures. To ensure that the children
were concentrating on the story, they were given two
informal comprehension questions during the course of
the book reading, such as ÔWhat animal is this?Õ and
ÔWhy is the fox running away?Õ Most children found
these questions easy.
Each of the target words was included twice in the
story, each time accompanying an illustration of that
word. Immediately after the first reading of the story,
the child was asked to point to the target areas on the
picture of the Gruffalo in the same way as they had in
pre-testing. Again, corrective feedback was given. After
spending at least 30 minutes on other tasks, the chil-
dren were shown a picture of the Gruffalo and were
asked to recall each of the target words. For instance,
the experimenter would point to the Gruffalo’s tusks
and ask ÔCan you remember what these were called?Õ
Again, they were given corrective feedback. Their per-
formance on this task was recorded as the Ôrecall scoreÕ.
Finally, they were read the story again, and given an-
other recognition test using the picture of the Gruffalo.
Responses were recorded to give the Ôrecognition scoreÕ.
Phonological awareness. Phonological awareness
was assessed by means of three different tests, invol-
ving syllable, rime and initial phoneme matching. All of
the tasks used followed the two alternative forced-
choice format used by Locke (1997). The child was
introduced to a puppet who liked to collect words with a
particular phonological relationship with the one it al-
ready had. For instance, Gerry Giraffe liked to collect
words with the same first syllable. For each trial, Gerry
held a picture card, and the children were asked, for
instance, ÔGerry has a picture of butter. Which of these
words, sandwich or button, has the same sound at the
beginning as butter ?Õ If the child said they didn’t know,
they were encouraged to Ôthink carefully and then
chooseÕ. When they had chosen, the cards were turned
over to see if they were correct – the correct alternative
had a coloured sticker on the back that was the same
colour as the cue card. The distracter card had a dif-
ferently coloured sticker. If they had picked correctly,
the experimenter said, for instance, ÔYes, that’s right,
butter and button have the same sound, ÔbutÕ, at the
beginning. Sandwich is the odd one out.Õ If they had
634 Julia M. Carroll and Margaret J. Snowling

5. chosen the wrong alternative, they were told ÔNo, button
and butter have the same sound, ÔbutÕ, at the beginning.
Sandwich is the odd one out.Õ In this way, the children
were given immediate feedback after every trial, as
previous researchers (e.g., Content, Kolinsky, Morais, &
Bertelson, 1986) had found that feedback on phonolo-
gical awareness tasks facilitates understanding of the
task requirements.
The tasks were presented in sets of eight with feed-
back following each trial. Most of the words used were
taken from an age of acquisition database (Morrison,
Chappell, & Ellis, 1997) as being words of high freq-
uency that were in children’s expressive vocabulary at
younger than three and a half years of age. The pictures
used were in the main taken from the Snodgrass and
Vanderwart (1980) picture set. A few words were not
from this database, however, and pictures of these words
were drawn freehand as black and white line drawings.
Syllable matching: The word used for the syllable
matching task all had two syllables. In 8 trials, the two
words matched according to the initial syllable (e.g.,
button – butter) and in 8 trials the matching was on the
basis of the final syllable (e.g., jigsaw – see-saw). Half of
the initial and half of the final matching trials had dis-
tracter items that were semantically related to the cue
word (e.g., puppy – puppet – rabbit).
Rime matching: There were 16 trials in the rime
matching task; 8 of these had distracter items that were
semantically related to the cue item (e.g., cat – dog –
hat), 4 had distracter items that were globally phono-
logical similar to the cue item (e.g., pin – tin – pen), 4
trials had distracter items that were unrelated to the
cue word.
Phoneme matching: In the phoneme matching task
the child was required to match items that started with
the same initial phoneme (e.g., pen – pig). The task
contained 16 trials. On four trials the distracter item
was semantically related to the cue word (e.g., sheep –
pig – shoe), and on four trials it was phonologically
related to the cue word (e.g., dish – beach – duck). On
four trials the distracter item was both semantically
and phonologically related to the cue word (e.g., moon –
sun – mouse), and on four trials it was unrelated to the
cue word.
Emergent literacy. Letter knowledge: Children were
shown each of the 26 lower-case letters of the alphabet
individually and asked if they knew what that letter
was. If they gave the letter name, they were asked if they
knew the letter sound. Letter-sound knowledge was
used in the analyses.
Reading: To assess early word recognition skills, a
test consisting of 42 of the earliest words children learn
was given (Hatcher, 2000). Children were shown the
words in sets of six and encouraged to read them. The
test was discontinued if the child did not know any of
the words from the first three sets.
Results
Mean scores for each group on individual tests are
presented in Table 1. To avoid the difficulties asso-
ciated with multiple comparisons on a large set of
tests, scores on each of the tasks were standardised,
and composite scores were created for each area of
interest. Group differences were assessed using
within-subjects analyses of variance, followed up by
planned comparisons between the groups in the
form of difference contrasts. Where appropriate,
differences between the control group and the two
high-risk groups on individual test scores are pre-
sented, and differences between the two high-risk
groups are discussed in terms of effect size.
Phonological processing
There was a significant effect of group on the
phonological processing composite score (F(2,32) ¼
25.01, p < .001), which included the measures of
expressive phonology (picture naming), nonword
repetition and mispronunciation detection. Differ-
ence contrasts showed that the three groups differed
significantly from each other (control vs. family:
F ¼ 18.857, p < .001, family vs. speech: F ¼ 27.907,
p < .001), with the family-risk children scoring in
between the controls and the speech-impaired chil-
dren. As anticipated, both high-risk groups showed
difficulties in basic phonological processes, and this
was more pronounced for the speech-impaired chil-
dren. Differences between the two high-risk groups
were large for measures of output phonology (ex-
pressive naming d ¼ .97; nonword repetition,
d ¼ 1.33), reflecting the selection procedure. In
contrast, the subgroup difference on the input
measure of mispronunciation detection was small
(d ¼ .13).
Figure 1 shows the distributions of the scores of
the children in the three groups on the expressive
phonology (picture-naming) task in terms of per-
centage consonants correct. All of the children in the
control group scored at least 80% consonants cor-
rect. The children with speech difficulties showed a
much wider range, from 25% to 96% consonants
correct. Six of the 17 children in the family-risk and
13/17 of those in the speech-impaired groups scored
below the lowest-scoring control child. Given the fact
Control Family-risk Speech-imp.
Figure 1 Individual scores on the expressive phonology
task by group
Children at risk of reading difficulties 635

6. that the subjects were individually matched, it was
not appropriate to use standard 2 · 2 Chi-square
analyses, and the data was analysed as 17 pairs in
which the control and the at-risk child were either
concordant or discordant for the presence of speech
difficulties. Both the analyses, for the family-risk
and for the speech-impaired groups, were signific-
ant, indicating that speech production difficulties
were more common in the family-risk group (v2
¼ 6,
df ¼ 1, p < .05) as well as in the speech-impaired
group (v2
¼ 13, df ¼ 1, p < .01).
Phonological learning
There was a significant effect of group on the
Phonological Learning composite (F(2,26) ¼ 6.020,
p < .01), which included the recognition and recall
measures from the Gruffalo task. In this case, the
control children outperformed both the family-risk
and the speech-impaired groups (F(1,13) ¼ 7.631,
p < .05, and F(1,13) ¼ 19.32, p < .001, respectively),
who did not differ from one another (F(1,13) ¼ 2.408,
p ¼ ns).
Phonological awareness
A composite phonological awareness score was cre-
ated by summing the standardised scores on the
syllable, rime and initial phoneme matching tasks. A
main effect of group was again found on this variable
(F(2,28) ¼ 4.404, p < .05). Difference contrasts
showed that the control children outperformed the
family-risk children (F(1,14) ¼ 9.00, p < .01) and the
family-risk and speech-impaired children did not
differ (F(1,14) ¼ 3.475, p ¼ ns). Examination of the
distribution of scores on the phonological awareness
tasks suggests that there are larger differences be-
tween the control group and the high-risk groups on
the rime and initial phoneme matching tasks than
on the syllable matching task. Given the non-normal
distribution on individual phonological awareness
tests, non-parametric tests were used, which con-
firmed the hypothesis: there was no significant dif-
ference between the groups on the Syllable task
(v2
¼ 4.667, df ¼ 2, p ¼ ns), but there were signific-
ant differences on the Rime (v2
¼ 8.373, df ¼ 2,
p < .05) and Initial Phoneme matching tasks
(v2
¼ 8.517, df ¼ 2, p < .05). Effect sizes are not
presented, again because of the non-normal dis-
tribution of the individual test scores.
Literacy measures
A composite literacy variable was created by sum-
ming the standardised scores of the letter-knowledge
and early word recognition tasks. A main effect of
group was again found (F(2,32) ¼ 4.189, p < .05).
Difference contrasts showed that, contrary to pre-
diction, the family-risk group did not differ sig-
nificantly from controls (F(1,16) ¼ 1.94, p ¼ ns), but
was performing significantly better than the children
with speech difficulties (F(1,16) ¼ 5.18, p < .05).
However, examination of the mean scores on the
reading and letter-knowledge tasks separately pre-
sents a somewhat different picture. It is important to
interpret sub-group differences cautiously given the
high degree of variability, especially in word re-
cognition. Nonetheless, further analyses suggest
that the family-risk and speech-impaired groups
both show lower levels of reading accuracy than
controls (F(1,32) ¼ 4.436, p < .05) and do not differ
from each other (d ¼ .18). For letter knowledge, there
is a trend suggesting an overall group difference
(F(1,32) ¼ 3.297, p ¼ .05), with the speech-impaired
children having significantly poorer knowledge of
letters than the family-risk group (d ¼ .49).
Discussion
This study explored the similarities in cognitive
profile between children with a family history of
dyslexia and children with speech problems, in an
attempt to assess their relative risk of reading
problems. On the basis of previous research, we as-
sumed that children in both groups could be con-
sidered at high risk of reading difficulties, and
predicted that they would show similar weaknesses
in phonological skills. In line with this prediction, the
performance of the two groups on tests of phonolo-
gical processing and phonological learning was im-
paired relative to that of controls at low risk of
reading failure of similar age and educational
experience. The two high-risk groups were also
found to have more poorly developed phonological
awareness and word recognition skills than controls,
and the speech-impaired group had rather less well-
developed letter knowledge.
The fact that the three groups of children had
similar receptive vocabulary rules out the possibility
that the phonological difficulties of the two high-risk
groups were a consequence of generally poor lan-
guage development. Moreover, the two high-risk
groups did not differ in their performance on the
perceptual task involving the detection of mispro-
nunciations in words. Given our recruitment proce-
dure, it was not surprising that the children with
speech impairments scored more poorly than con-
trols on the two tests of output phonology. However,
although nonword repetition deficits in the family-
risk group were predicted, the degree of impairment
in expressive phonology (naming) was unanticip-
ated. The difficulties observed in expressive phono-
logy and nonword repetition confirmed that output
phonological deficits are implicated in the family risk
of dyslexia, though these are less severe than those
observed among children with speech impairments.
Importantly, the two high-risk groups were impaired
to a similar degree on a dynamic task requiring
phonological learning, in spite of the fact that they
636 Julia M. Carroll and Margaret J. Snowling

7. were matched with controls in consolidated voca-
bulary knowledge on the picture vocabulary test.
Although our data do not allow us to draw inferences
about causation, these findings suggest that the two
high-risk groups have difficulties with the encoding,
storage or retrieval processes involved in new word
learning. Put another way, they have difficulty in
establishing the phonological representations that
underlie the accurate retrieval of new phonological
forms. We propose such a difficulty implies that,
irrespective of whether or not the meaning of a new
word can be acquired easily, it will be difficult for
these children to retrieve its name. More generally,
such a difficulty could explain these children’s
difficulty in verbal short-term memory, confronta-
tion and rapid naming tasks (Wagner & Torgesen,
1987).
As predicted, the difficulties of the high-risk
groups were not limited to implicit phonological
processes such as nonword repetition. In line with
the developmental progression of explicit phonolo-
gical awareness, the high-risk groups did not differ
from controls in syllable matching but they showed
lower performance on the rime and initial phoneme
matching tasks. Importantly, in this study, the rime
and phoneme tasks contained distracter items mat-
ched for global similarity to the cue words. This
manipulation precluded the use of a strategy based
on overall acoustic similarity to match the target and
response items (Byrne & Fielding-Barnsley, 1993).
Rather, it was necessary for the child to have access
to the segmental structure of the words. Thus, suc-
cessful performance on these tasks required access
to well-specified, rather than global, phonological
representations (Carroll & Snowling, 2001). In line
with these findings, Bird et al. (1995) suggested that
nonword reading and spelling difficulties observed
among speech-impaired children might be explained
by the fact that these children still represent words
as undifferentiated global wholes, rather than as a
series of segmented phonemes.
The difficulties that the family-risk and speech-
impaired groups showed in phonological awareness
when compared with controls confirmed their status
at high risk of reading difficulties. In line with this,
their concurrent reading attainments were poorer
than those of children of the same age and verbal
ability, as measured by a test of early word recogni-
tion skills suitable for children making their first
steps into literacy. As already mentioned, however,
an unexpected finding was there was only a trend
suggestive of differences between the groups in letter
knowledge. Furthermore, contrary to previous re-
search (Scarborough, 1990; Gallagher et al., 2000;
Byrne, Fielding-Barnsley, Ashley, & Larsen, 1997),
children with a family history of dyslexia did not
differ from the controls in the number of letter
sounds they knew. A feature of the present study
that may account for this discrepancy is that most of
the children in the family-risk group were recruited
because they had an older sibling who had already
been diagnosed as dyslexic (and was often receiving
intervention). Gallagher et al. (2000) found that
parents of children Ôat riskÕ of dyslexia spent more
time teaching letters to their pre-school children
than parents of control children. It may be that
parents who have at least one dyslexic child already
are more attuned to the need to help their child learn
letters than if their experience of dyslexia was their
own and many years ago. In contrast, the parents of
children with speech difficulties generally do not
associate these oral language problems with a risk of
written language difficulties and therefore, it can be
surmised, do not train letter skills.
Finally, it is interesting to note that, although
there is a close relationship between a child’s letter
knowledge and their initial sound matching skills
(Bowey, 1994; Johnston, Anderson, & Holligan,
1996), the lower performance of the family-risk
group could not be accounted for by poor letter
knowledge because they were performing within the
average range on this test. This finding underlines
the fact that children at high risk of reading diffi-
culties require training in explicit phonological
awareness; tuition in letter knowledge alone is not
sufficient to allow them to solve phonological seg-
mentation and categorisation tasks.
To conclude, the results of the present study
confirm the view that children with expressive
speech impairments in the absence of language
problems are at high risk of reading difficulties and
are on a continuum with children at family risk of
dyslexia. It is proposed that the shared risk factor is
a problem of phonological processing that can be
traced to poorly specified phonological representa-
tions. According to Walley (1993), vocabulary growth
during the pre-school years causes the phonological
representations of words to develop from global to
segmental form. Segmental phonological represen-
tations are required for the development of phoneme
awareness and underpin the acquisition of proficient
reading skills (i.e., decoding). However, the present
findings add to others that point to the fact that
there can be a dissociation between vocabulary and
phonological skills (e.g., Snowling, Van Wagtendonk,
& Stafford, 1988; Swan & Goswami, 1997). Thus,
the two groups of children at high risk of reading
difficulties presented with phonological processing
problems in the absence of vocabulary impairments.
In spite of their similar levels of crystallised voca-
bulary knowledge, the two high-risk groups shared a
deficit in phonological learning that compromised
their ability to acquire new words. We propose that
this difficulty provides a parsimonious explanation
for the range of phonological difficulties they
showed. If such children are unable to create seg-
mentally organised phonological representations,
then their recall of new words will suffer, although
they may show fewer difficulties on tests of recogni-
tion memory for these novel items. They will have
Children at risk of reading difficulties 637

8. difficulty in discriminating between accurate pro-
nunciations of familiar words and pronunciations
that are minimally distorted by a single phoneme
change. They will also show deficits on tasks that
require access to well-specified representations of
words in order to match words that share phonolo-
gical segments rather than global acoustic similarity
with each other. The findings of the present study
are consistent with these predictions. Moreover, as
has been argued elsewhere (Snowling, 2000b), chil-
dren who come to the task of learning to read with
poorly specified phonological representations have
difficulties in setting up mappings between ortho-
graphic and phonological sequences (Harm & Sei-
denberg, 1999).
The findings of the study also extend the evidence
that children with language impairments have diffi-
culty with the quick incidental learning of words that
are embedded in narrative form (Rice et al., 1994) to
the case of children with oral speech impairments.
Moreover, their difficulties were more marked for
production than for comprehension of these items. It
is possible therefore that, in the longer term, these
children will begin to show deficits in vocabulary
relative to their peers, aggravated by their poor
reading skills. Together with the other results of this
study, these findings indicate that the remediation of
speech difficulties in pre-school and school-aged
children is important not only for the successful
acquisition of reading but also to ensure the con-
tinued normal rate of growth of spoken vocabulary.
There are a number of limitations of the present
study that could have affected results. First, it is
important to note that the study does not speak to
the developmental precursors of the speech difficul-
ties for which the speech group were being treated.
The findings do not rule out the possible relevance of
earlier language delays that may have resolved in
either of the high-risk groups. Second, the children
in this study were studied at a relatively early stage
in their literacy development when there is consid-
erable variability in performance even in typically
developing children. This variability, together with
developmental constraints on some of the skills,
necessarily reduced the statistical power to detect
group differences. Indeed, many of the differences
reported for the variables assessed separately are
not significant if a strict Bonferroni correction is
applied to account for multiple comparisons. How-
ever, we would argue that to ignore such group dif-
ferences, where these have been predicted, would be
overly conservative. Scarborough and Dobrich
(1990) have pointed out that there is a tendency,
both in research and clinical practice, to overlook
subtle impairments in children with language delays
when skills, such as reading, are measured at a time
when normal development is at a plateau. This
argument could be applied to the present data set in
which many of the control children gained low scores
on the tests of reading-related skills. According to
Scarborough and Dobrich, it is when skills are in
ÔascendancyÕ and changing rapidly that language-
based deficits are more easily detectable. In sum-
mary, the present findings are important. Despite
the developmental limitations of some of the meas-
ures, the study provides clear evidence of difficulties
in a range of phonological skills relevant to literacy in
these two groups of children at high risk of reading
difficulties and argues that there is a continuum of
risk between speech difficulties and dyslexia.
Acknowledgements
This research was carried out as part of the first
author’s doctoral work, with support from a BBSRC
studentship. Preparation of the manuscript was
supported by an ESRC postdoctoral fellowship no.
T026271158.
We thank the parents, teachers and speech ther-
apists who helped, and all of the children who took
part in this study.
Correspondence to
Julia Carroll, Department of Psychology, University
of York, York YO10 5DD, UK; Email: j.carroll@
psych.york.ac.uk
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Manuscript accepted 19 May 2003
640 Julia M. Carroll and Margaret J. Snowling