Why preschoolers with unclear speech are at risk of later reading problems: red flags to seek help

For over 20 years we’ve known that preschoolers with speech sound disorders have an increased risk of later reading difficulties (e.g. Bird et al., 1995).

Why do speech problems contribute to reading problems?

Spoken words and written words rely on the same underlying knowledge: mental models we develop about the speech sounds that make up our spoken words. When kids learn to read, they use their sound models to sound out written words.

For example, you need to have good mental models for the sounds /m/, /ae/ and /t/ to read the word ‘mat’ correctly. (You also need to be able to link the letters to speech sounds to be able to decode the letters ‘m’, ‘a’, and ‘t’ into the speech sounds /m/, /ae/, and /t/, and to then blend them together to say /maet/ or ‘mat’.)

Preschooler speech-related red flags for later reading problems

Preschoolers are at a heightened risk for later reading problems if their speech features lots of ‘deletion errors’ and/or ‘atypical errors’, or if they have significant problems saying words with more than two syllables (‘polysyllables’).

Why these error patterns in particular?

For people who are not speech pathologists (and many of us who are!), the explanation can get a bit abstract and jargon-laden. I’ll use concrete examples and try to explain some of the key terms as we go:

Mark is a 4 1/2 year old boy with a mild-moderate speech sound disorder. His immediate family can usually understand him, but other relatives and strangers have difficulties, especially in conversation. He says ‘du’ for ‘duck’ and ‘nana’ for ‘banana’. The errors – called final consonant deletion and weak syllable deletion, respectively – are both common types of developmental error patterns called ‘phonological processes‘. They are examples of ‘deletion errors’ because one or more sounds are left out when Mark tries to say words.
Anna, a 4 year old girl, has a more severe speech sound disorder than Mark. Her mum can usually understand Anna in context with the aid of gestures, though her dad and other family members struggle. Strangers have great difficulty understanding Anna, much to her frustration. She says ‘it’ for ‘bit’, ‘osh’ for ‘stop’, and ‘ark’ for ‘Matt’ (her brother): these are atypical speech errors, including initial consonant deletion, fricative substitutions for stops, vowel errors, and backing of alveolar consonants. (Practice note: the first thing I would recommend to Anna’s family would be to get Anna’s hearing tested by a qualified audiologist, for the reasons set out here).
Zach, aged 5 years, was a late talker: he said his first words at around 2 years of age. He is mostly intelligible, although he makes some deletion errors. He doesn’t seem to have many words for his age and speaks mostly in simple one and two-syllable words. When asked to name or repeat polysyllabic words like ‘tyrannosaurus’, ‘calculator’ and ‘thermometer’, however, he makes lots more errors than he does with one or two-syllable words. He sometimes deletes or adds consonants and vowels, deletes weak syllables, and/or puts stress on the wrong syllables (e.g. ‘THERmometer’). He also gets lots of the sounds wrong making ‘substitution errors’, e.g. /t/ for /k/ (which is a ‘fronting’ error he should no longer be making) and /w/ for /r/ (which is a ‘gliding’ error that is still age-appropriate).

Deletion errors, like Mark’s, and atypical errors, like Anna’s, are both red flags for reading difficulties (e.g. Dodd, 2005; Leitão & Fletcher, 2004, Anthony et al., 2010, Shriberg et al., 2009):

Mark’s deletion errors may be symptoms that:
- he has problems storing, encoding (i.e. breaking information into a form he understands) or retrieving his models of speech sounds (e.g. Shriberg et al., 2005);
- his models for some speech sounds are insufficient or underspecified (e.g. Anthony et al., 2010); and/or
- he might have a developmental language disorder (e.g. Macrae & Tyler, 2014).

Anna’s speech errors are developmentally unusual. Her models for several speech sounds are very different to the correct (adult) forms of the sounds, and it is likely that she would struggle with phonological awareness tasks linked to reading success, like decoding letters into the correct speech sounds and then blending the speech sounds into words (e.g. Preston et al., 2013).

Why test preschoolers’ polysyllables?

Many norm-referenced speech assessments focus primarily on single and two-syllable words. But you can get a lot of good information about a child’s speech sound ‘models’ by testing longer and more complex words.

Zach, who has significant problems with polysyllables, is also at risk of later reading problems. In one Finnish study, late talkers produced on average fewer and less accurate polysyllabic words (like ‘ambulance’, ‘helicopter’ and ‘butterfly’) at 30 months than typically developing peers, and went on to demonstrate poorer reading skills when they started school (Turunen, 2003). This was consistent with a 1999 study by Larrivee and Catts who found that consonant accuracy on polysyllables accounted, significantly, for the variance of children in reading skills after a year of formal reading instruction.

In a recent study, Dr Sarah Masso and colleagues looked (amongst other things) at the polysyllabic speech skills of 93 Australian preschool children (aged 4-5;5 years) diagnosed with speech sound disorders. After testing the kids’ polysyllable speech skills, phonological awareness skills, receptive vocabulary, and print knowledge, they were able to sort the children into two ‘clusters’:

children, like Zach, with low polysyllabic accuracy, including frequent deletion errors, stress and other timing errors (the ‘low group’); and
children with moderate polysyllabic accuracy, including fewer deletion errors (the ‘moderate group’).

Compared to the moderate group, the low group achieved significantly lower scores on tests of:

phonological awareness;
memory for digits;
rapid naming; and
receptive vocabulary.

In other words, polysyllable test results may be a good indicator of preschoolers who demonstrate poor performance on the phonological processing tasks that are linked to later reading outcomes. (They may also help identify children with relatively weaker vocabulary skills, although in the study, all children were found to have receptive vocabulary scores within the average range.)

Masso’s study had some important limitations, including no ‘typically developing’ control group, no analysis of speech input versus output knowledge, and a lack of norms for the polysyllable test used in the study, known as the ‘Word Level Analysis of Polysyllables’ or ‘WAP’. Disturbingly, many of the participants (across both clusters) had very poor knowledge of letter names and letter sounds: 35.5% of the kids had no knowledge whatsoever of letter names or sounds.

Clinical bottom line

Preschoolers with unclear speech and speech sound disorders are at a heightened risk for later reading difficulties, especially if their speech is marked by significant deletion and atypical speech error patterns. Speech pathologists should use polysyllable speech tests when assessing children with suspected speech, language and/or reading difficulties. Although by no means the only factors that lead to reading difficulties, poor polysyllable production and inadequate phonological awareness skills are essential factors to examine when assessing a preschooler’s risk of later reading difficulties, and in deciding whether your preschooler could benefit from extra help.

Related articles:

Principal source: Masso, S., Baker, E., McLeod, S., & Wang, C. (2017). Polysyllable Speech Accuracy and Predictors of Later Literacy Development in Preschool Children with Speech Sound Disorders. Journal of Speech, Language and Hearing Research, 1-14.

Image: http://tinyurl.com/y7d97svx

Hi there, I’m David Kinnane.

Principal Speech Pathologist, Banter Speech & Language

Our talented team of certified practising speech pathologists provide unhurried, personalised and evidence-based speech pathology care to children and adults in the Inner West of Sydney and beyond, both in our clinic and via telehealth.

Why preschoolers with unclear speech are at risk of later reading problems: red flags to seek help

Why do speech problems contribute to reading problems?