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This article originally appeared in the May 2018 PROFILE issue of Open Access Government Specific Impairment (SLI) versus Speech Sound Disorders (SSD) The important differences between Specific Language Impairment (SLI) in children and Speech Sound Disorders (SSD) in children are placed under the spotlight by Mabel L. Rice, Fred & Virginia Merrill Distinguished Professor of Advanced Studies at the University of Kansas

round the world young chil- they are hearing. Their first job is to SSD can be obvious to adult listeners dren are expected to learn refine them to match the ones they of young children. Young children’s the language they overhear in need and to drop the ones that may attempts to talk can be unintelligible, Aconversations around them. This is a not matter and to develop the motor especially when they are very young. robust, spontaneous ability of humans, control needed to do that. If unintelligibility persists as children unlike, for example, , which age, it becomes noticeable and a must be explicitly taught. One promi- Humans at birth are equipped with matter of concern because it is nent scholar of children’s language motor movements for breathing, not “typical.” Some mispronunciations acquisition once put it this way: “… sucking and swallowing (basic func- are understandable but regarded as there is virtually no way to prevent it tions for survival), along with a wide immature, such as “wabbit” for “rabbit”, from happening short of raising a child range of sounds. Some vocalisations “thoup” for “soup”, or “bawoon” for in a barrel.”1 serve communicative purposes, and “balloon.” Scholars have tracked the some are biological (such as burps or order in which children learn their Although true of most children, chil- coughs). Between one and two years speech sounds and have developed dren with Specific Language Impair- of age, babies master more refined age norms for evaluating whether a ment (SLI) are the exceptions to this tongue, lips and palatal movements child meets age expectations4. The assumption. These are children who do needed for speaking the words and prevalence of SSD in 4-6-year-old not have overt neurodevelopmental sentences of a language. This children in population-based cohorts disorders, hearing impairments, or requires a fine-tuned synchrony of is approximately 3-6%5 and the condi- other obvious causes of developmental muscles, sound perception and the tion appears to resolve in 75% of disorders and who live in ordinary cognitive centres of the brain. The children by age 66. families. Yet they are later than other output is a sequenced speech children in learning a language and pattern, such as what we hear in a People often assume SSD is the same are at risk for persistent low language phone conversation. as SLI, such that children’s speech abilities into adulthood. The best abilities reflect their underlying estimates for the prevalence of SLI are The second part of the human language abilities or vice versa. This is 7-10% of children at school entry (5-6 language capacity is more covert, a not true. In the most precise study of years).2,3 matter of cognitive processes in the a population-based sample of 5-year- brain that do not require a speech old children, the co-occurrence of SLI is often confused with system. For example, deaf speech and language impairments, Sound Disorders (SSD) in children. children can acquire a language once adjusting for age expectations, Between one and five years of age system that can be expressed in phys- was estimated at less than 2%5. For children are learning two distinctly ical signs of the hands, face and body the children with SLI, speech impair- different parts of the human language postures. Language emerges in young ment was evident in approximately capacity. One is the production of children first in short utterances 5-8% of the children. The authors speech sounds needed in their native that lengthen with age. In English, lan- concluded that SSD and SLI are inde- language. In the beginning, children guage emerges as one or two words pendent; they are not likely to co-occur. can produce more sounds than they at a time, which relatively quickly Thus, SSD is not a diagnostic marker need for the language or expand to phrases or sentences. of SLI and presumably, the two condi-

310 PROFILE tions do not share a common causal says “why ah de wabbits wed?” The References pathway. substitution of w/r in “rabbit” and 1. Pinker S. Language learnability and . Cam- “red”, along with the omission of the bridge, MA: Harvard University Press; 1984. The non-overlap of SLI and SSD carries final /r/ in the word “are,” are not 2. Tomblin JB, Records NL, Buckwalter P, Zhang X, Smith E, O'Brien M. The prevalence of specific language impairment in kinder- implications for public health services unusual speech errors in the speech garten children. J Speech Hear Res. 1997;40:1245-1260. and for scientific studies of the nature of young boys. 3. Norbury CF, Gooch D, Wray C, et al. The impact of nonverbal ability and origins of SLI and SSD. on prevalence and clinical presentation of : Such errors are quite noticeable evidence from a population study. Journal of Child Psychology & . 2016;57(11):1247-1257. • A big issue for public health services although they often do not interfere 4. Goldman R, Fristoe M. Goldman Fristoe Test of Articulation-2 is that children with SLI are likely to with adults’ understanding of the (2nd Edition). Circle Pines, MN: American Guidance Service; be overlooked as needing language intended meanings. The other boy, 2000.

intervention services, perhaps in part dressed in green, asks a question 5. Shriberg LD, Tomblin JB, McSweeny JL. Prevalence of speech because of the fact that SSD may be formulated in the adult grammar as: delay in 6-year-old children and comorbidity with language impairment. J Speech Lang Hear Res. 1999;42:1461-1481. obvious to adults/caregivers, but SLI “why is/are that rabbit/those rabbits is not7. red?” The boy says “Why that red?”, a 6. Shriberg LD. Five subtypes of developmental phonological disorders. Clinical Communication Disorders 1994;4:38-53. sentence consistent with the gram- 7. Rice ML. Specific Language Impairment in Children. https://ww- • SSD is likely to resolve with age mar rules for children this age with wopenaccessgovernmentorg/specific-language-impairment-in- 7 (children are likely to “outgrow” it) SLI . He demonstrates a deficiency in chi 2017.

whereas SLI is likely to persist into sentence structure, with the omission 8. Catts HW, Fey ME, Weismer SE, Bridges MS. The relationship adulthood7. of the obligatory copula form of BE between language and reading abilities. In: Tomblin JB, Nippold MA, eds. Understanding individual differences in language (“is”’ or “are”) and the substitution of a development across the school years New York City, New York: • At school entry, SLI predicts later pronoun (“that”) for the common Psychology Press; 2014:144-165. 8 reading impairments whereas SSD noun “rabbit.” Furthermore, the 9. Sices L, Taylor HG, Freebairn L, Hansen A, Lewis B. Relationship predicts weakly, if at all, once specification of singular versus plural between speech-sound disorders and early skills in preschool-age children: Impact of comorbid langauge impair- adjusted for co-occurring language for the noun phrase is vague because ment. J Dev Behav Pediatr,. 2007;6:438-447. impairments.9,10 the noun information is underspeci- 10. Hayiou-Thomas ME, Carroll JM, Leavett R, Hulme C, Snowling fied. His articulation of speech sounds MJ. When does matter for literacy? The • Scientific studies of children’s com- is at adult levels and his meaning is role of disordered speech errors, co-occurring language impair- ment and family risk of . Journal of Child Psychology munication problems in medical con- effectively conveyed. and Psychiatry. 2017;58(2):197-205. ditions should differentiate between 11. Rice ML, Russell JS, Frederick T, et al. Risk for speech and language SLI and SSD. A recent study of children Although the speech sound errors of impairments in pre-school aged HIV-exposed uninfected children exposed to Human Immunodefi- the child with SSD are likely to be with in utero combination antiretroviral exposure. The Pediatric Infectious Disease Journal. Accepted Dec 2017. ciency Virus (HIV) is the first report of noticed and to generate attempts by SSD outcomes compared to primary adults to correct the problem, the language impairments (i.e., without grammar errors of the child with SLI other developmental disorders). The are less likely to be noticed or under- risk for language impairments in the stood as flags for concern. Yet it is the children was higher than population child in green who is at higher risk of norms but the risk for SSD was not adverse developmental outcomes elevated.11 than the child in purple, who is more likely to “outgrow” the SSD and less Examples of how children talk can likely to encounter problems with illustrate the differences between SLI literacy, school achievement, or and SSD. Consider two 5-year-old long-term persistence of subtle but Mabel L. Rice boys. They are talking about a picture very important elements of grammar Fred & Virginia Merrill Distinguished of red rabbits. One, dressed in purple, and vocabulary. Our research and Professor of Advanced Studies has an SSD, apparent in his mispro- our service systems will be improved University of Kansas nunciations of the speech sounds by increased recognition of the Tel: +1 785 864 4570 needed to say “why are the rabbits important differences between SLI [email protected] red.” Within his speech system, he and SSD.

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