Abstract
Purpose
The aims of this study were (a) to examine the relationship between speech intelligibility at the age of 5 years and literacy skills at the age of 8 years, (b) to explore the possible mediating or moderating role of broader language skills at 5 years in the relationship of interest, and (c) to assess whether the potential risk factors (child gender; maternal education levels; and family history of speech, language, reading, and writing difficulties) influence the relationship between speech intelligibility and literacy in terms of moderated mediation effects.
Method
We used mother-reported questionnaire data on 16,184 children participating in the population-based, prospective Norwegian Mother, Father and Child Cohort Study as well as conducted linear regression analyses using the PROCESS macro in SPSS. In addition, logistic regression was conducted to make predictions about risk.
Results
The association between speech intelligibility at 5 years and literacy skills at 8 years was statistically significant (β = .168, p < .001). Children with speech problems at 5 years had a risk ratio of 2.38 (95% CI [2.10, 2.70]) and an odds ratio of 2.74 (95% CI [2.35, 3.19]), as compared to children without such problems. Broader language skills at 5 years partially mediated the relationship between speech intelligibility at 5 years and literacy at 8 years, and the effect of language skills appeared to be moderated by child gender, a family history of language difficulties, a family history of reading difficulties, and maternal education.
Conclusions
Severity of speech problems indexed by parent-reported speech intelligibility in preschool predicted school-age literacy problems. Broader language skills are a crucial mediating mechanism through which these problems are linked, and the mediated relationship is amplified by female gender, low maternal education, family history of language difficulties, and family history of reading difficulties. The findings call for increased use of a multiple-risk model when planning early interventions in children with unclear speech.

References
- American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.).
-
Baye, A., & Monseur, C. (2016). Gender differences in variability and extreme scores in an international context.Large-scale Assessments in Education, 4, 1–16. https://doi.org/10.1186/s40536-015-0015-x -
Bird, J., Bishop, D. V. M., & Freeman, N. H. (1995). Phonological awareness and literacy development in children with expressive phonological impairments.Journal of Speech and Hearing Research, 38(2), 446–462. https://doi.org/10.1044/jshr.3802.446 -
Bishop, D. V. M., & Adams, C. (1990). A prospective study of the relationship between specific language impairment, phonological disorders and reading retardation.The Journal of Child Psychology and Psychiatry, 31(7), 1027–1050. https://doi.org/10.1111/j.1469-7610.1990.tb00844.x -
Bleses, D., Makransky, G., Dale, P., Højen, A., & Ari, B. (2016). Early productive vocabulary predicts academic achievement 10 years later.Applied Psycholinguistics, 37(6), 1461–1476. https://doi.org/10.1017/S0142716416000060 -
Campbell, T. F., Dollaghan, C. A., Rockette, H. E., Paradise, J. L., Feldman, H. M., Shriberg, L. D., Sabo, D. L., & Kurs-Lasky, M. (2003). Risk factors for speech delay of unknown origin in 3-year-old children.Child Development, 74(2), 346–357. https://doi.org/10.1111/1467-8624.7402002 -
Chaimay, B., Thinkhamrop, B., & Thinkhamrop, J. (2006). Risk factors associated with language development problems in childhood–A literature review.Journal of the Medical Association of Thailand, 89(7), 1080–1086. -
Coplan, J., & Gleason, J. R. (1988). Unclear speech: Recognition and significance of unintelligible speech in preschool children.Pediatrics, 82(3), 447–452. -
DeThorne, L. S., Hart, S. A., Petrill, S. A., Deater-Deckard, K., Thompson, L. A., Schatschneider, C., & Davison, M. D. (2006). Children's history of speech-language difficulties: Genetic influences and associations with reading-related measures.Journal of Speech, Language, and Hearing Research, 49(6), 1280–1293. https://doi.org/10.1044/1092-4388(2006/092) -
Eadie, P., Morgan, A., Ukoumunne, O. C., Ttofari Eecen, K., Wake, M., & Reilly, S. (2014). Speech sound disorder at 4 years: Prevalence, comorbidities, and predictors in a community cohort of children.Developmental Medicine & Child Neurology, 57(6), 578–584. https://doi.org/10.1111/dmcn.12635 -
Ebert, K. D. (2017). Convergence between parent report and direct assessment of language and attention in culturally and linguistically diverse children.PLOS ONE, 12(7), Article e0180598. https://doi.org/10.1371/journal.pone.0180598 -
Eriksson, M., Marschik, P. B., Tulviste, T., Almgren, M., Pérez Pereira, M., Wehberg, S., Marjanovič-Umek, L., Gayraud, F., Kovacevic, M., & Gallego, C. (2012). Differences between girls and boys in emerging language skills: Evidence from 10 language communities.British Journal of Developmental Psychology, 30(2), 326–343. https://doi.org/10.1111/j.2044-835X.2011.2042.x -
Feldman, H. M., Dale, P. S., Campbell, T. F., Colborn, D. K., Kurs-Lasky, M., Rockette, H. E., & Paradise, J. L. (2005). Concurrent and predictive validity of parent reports of child language at ages 2 and 3 years.Child Development, 76(4), 856–868. https://doi.org/10.1111/j.1467-8624.2005.00882.x -
Gadermann, A. M., Guhn, M., & Zumbo, B. D. (2012). Estimating ordinal reliability for Likert-type and ordinal item response data: A conceptual, empirical, and practical guide.Practical Assessment, Research & Evaluation, 17, 1–13. -
Harrison, L. J., & McLeod, S. (2010). Risk and protective factors associated with speech and language impairment in a nationally representative sample of 4- to 5-year-old children.Journal of Speech, Language, and Hearing Research, 53(2), 508–529. https://doi.org/10.1044/1092-4388(2009/08-0086) -
Hawke, J. L., Olson, R. K., Willcutt, E. G., Wadsworth, S. J., & DeFries, J. C. (2009). Gender ratios for reading difficulties.Dyslexia, 15(3), 239–242. https://doi.org/10.1002/dys.389 -
Hayes, A. F. (2013). Introduction to mediation, moderation, and conditional process analysis: A regression-based approach. Guilford Press. -
Hayiou-Thomas, M. E., Carroll, J. M., Leavett, R., Hulme, C., & Snowling, M. J. (2017). When does speech sound disorder matter for literacy? The role of disordered speech errors, co-occurring language impairment and family risk of dyslexia.The Journal of Child Psychology and Psychiatry, 58(2), 197–205. https://doi.org/10.1111/jcpp.12648 -
Helland, S. S., Røysamb, E., Wang, M. V., & Gustavson, K. (2018). Language difficulties and internalizing problems: Bidirectional associations from 18 months to 8 years among boys and girls.Development and Psychopathology, 30(4), 1239–1252. https://doi.org/10.1017/S0954579417001559 -
Hodge, M. N., & Whitehill, T. L. (2013). Intelligibility impairments.InJ. S. Damico, N. Müller, & M. J. Ball (Eds.), The handbook of language and speech disorders (pp. 99–114). Wiley-Blackwell. https://doi.org/10.1002/9781444318975.ch4 -
Hoff, E., Core, C., & Bridges, K. (2008). Non-word repetition assesses phonological memory and is related to vocabulary development in 20- to 24-month-olds.Journal of Child Language, 35(4), 903–916. https://doi.org/10.1017/S0305000908008751 -
Hulme, C., Nash, H. M., Gooch, D., Lervåg, A., & Snowling, M. J. (2015). The foundations of literacy development in children at familial risk of dyslexia.Psychological Science, 26(12), 1887–1886. https://doi.org/10.1177/0956797615603702 - IBM. (2015). IBM SPSS statistics for Windows
(Version 23.0) [Computer software] . -
Janson, H., & Smith, L. (2003). Norsk Manualsupplement til Ages and Stages Questionnaires (Norwegian Manual Supplement to Ages and Stages Questionnaires).RBUP Øst og Sør. -
Larrivee, L. S., & Catts, H. W. (1999). Early reading achievement in children with expressive phonological disorders.American Journal of Speech-Language Pathology, 8(2), 118–128. https://doi.org/10.1044/1058-0360.0802.118 -
Leitao, S., & Fletcher, J. (2004). Literacy outcomes for students with speech impairment: Long-term follow-up.International Journal of Language & Communication Disorders, 39(2), 245–256. https://doi.org/10.1080/13682820310001619478 -
Lewis, B. A., Freebairn, L. A., Tag, J., Ciesla, A. A., Iyengar, S. K., Stein, C. M., & Taylor, H. G. (2015). Adolescent outcomes of children with early speech sound disorders with and without language impairment.American Journal of Speech-Language Pathology, 24(2), 150–163. https://doi.org/10.1044/2014_AJSLP-14-0075 -
Lewis, B. A., Freebairn, L. A., & Taylor, H. G. (2000). Academic outcomes in children with histories of speech sound disorders.Journal of Communication Disorders, 33(1), 11–30. https://doi.org/10.1016/S0021-9924(99)00023-4 -
Libertus, M. E., Odic, D., Feigenson, L., & Halberda, J. (2015). A Developmental Vocabulary Assessment for Parents (DVAP): Validating parental report of vocabulary size in 2- to 7-year-old children.Journal of Cognition and Development, 16(3), 442–454. https://doi.org/10.1080/15248372.2013.835312 -
Magnus, P., Birke, C., Vejrup, K., Haugan, A., Alsaker, E., Daltveit, A. K., Handal, M., Haugen, M., Høiseth, G., Knudsen, G. P., Paltiel, L., Schreuder, P., Tambs, K., Vold, L., & Stoltenberg, C. (2016). Cohort profile update: The Norwegian Mother and Child Cohort Study (MoBa).International Journal of Epidemiology, 45(2), 382–388. https://doi.org/10.1093/ije/dyw029 -
Magnus, P., Irgens, L. M., Haug, K., Nystad, W., Skjærven, R., Stoltenberg, C. , & MoBa Study Group. (2006). Cohort profile: The Norwegian Mother and Child Cohort Study (MoBa).International Journal of Epidemiology, 35(5), 1146–1150. https://doi.org/10.1093/ije/dyl170 -
Nathan, L., Stackhouse, J., Goulandris, N., & Snowling, M. J. (2004). The development of early literacy skills among children with speech difficulties: A test of the “critical age hypothesis”.Journal of Speech, Language, and Hearing Research, 47(2), 377–391. https://doi.org/10.1044/1092-4388(2004/031) -
Nation, K., & Snowling, M. J. (2004). Beyond phonological skills: Broader language skills contribute to the development of reading.Journal of Research in Reading, 27(4), 342–356. https://doi.org/10.1111/j.1467-9817.2004.00238.x -
Nilsen, R. M., Vollset, S. E., Gjessing, H. K., Skjærven, R., Melve, K. K., & Schreuder, P. (2009). Self-selection and bias in a large prospective pregnancy cohort in Norway.Paediatric and Perinatal Epidemiology, 23(6), 597–608. https://doi.org/10.1111/j.1365-3016.2009.01062.x -
Overby, M. S., Trainin, G., Smit, A. B., Bernthal, J. E., & Nelson, R. (2012). Preliteracy speech sound production skill and later literacy outcomes: A study using the Templin Archive.Language, Speech, and Hearing Services in Schools, 43(1), 97–115. https://doi.org/10.1044/0161-1461(2011/10-0064) -
Pennington, B. F., & Bishop, D. V. M. (2009). Relations among speech, language, and reading disorders.Annual Review of Psychology, 60, 283–306. https://doi.org/10.1146/annurev.psych.60.110707.163548 -
Peterson, R. L., Pennington, B. F., Shriberg, L. D., & Boada, R. (2009). What influences literacy outcome in children with speech sound disorder?.Journal of Speech, Language, and Hearing Research, 52(5), 1175–1188. https://doi.org/10.1044/1092-4388(2009/08-0024) -
Plaut, D. C., & Kello, C. T. (1999). The emergence of phonology from the interplay of speech comprehension and production: A distributed connectionist approach.InB. MacWhinney (Ed.), The emergence of language (pp. 391–415). Erlbaum. -
Preston, J. L., & Edwards, M. L. (2010). Phonological awareness and types of sound errors in preschoolers with speech sound disorders.Journal of Speech, Language, and Hearing Research, 53(1), 44–60. https://doi.org/10.1044/1092-4388(2009/09-0021) -
Preston, J. L., Hull, M., & Edwards, M. L. (2013). Preschool speech error patterns predict articulation and phonological awareness outcomes in children with histories of speech sound disorders.American Journal of Speech-Language Pathology, 22(2), 173–184. https://doi.org/10.1044/1058-0360(2012/12-0022) -
Ramus, F., & Szenkovits, G. (2009). Understanding the nature of the phonological deficit.InK. Pugh & P. McCardle (Eds.), How children learn to read: Current issues and new directions in the integration of cognition, neurobiology and genetics of reading and dyslexia research and practice (pp. 153–169). Psychology Press. -
Richter, J., & Janson, H. (2007). A validation study of the Norwegian version of the Ages and Stages Questionnaires.Acta Paediatrica, 96(5), 748–752. https://doi.org/10.1111/j.1651-2227.2007.00246.x -
Rosenbaums, S., & Simon, P. (2016). Speech and language disorders in children: Implications for the Social Security Administration's Supplemental Security Income Program.National Academies Press. https://doi.org/10.17226/21872 -
Sachse, S., & Von Suchodoletz, W. (2008). Early identification of language delay by direct language assessment or parent report.Journal of Developmental & Behavioral Pediatrics, 29(1), 34–41. https://doi.org/10.1097/DBP.0b013e318146902a -
Schjølberg, S., Eadie, P., Zachrisson, H. D., Øyen, A.-S., & Prior, M. (2011). Predicting language development at age 18 months: Data from the Norwegian Mother and Child Cohort Study.Journal of Developmental & Behavioral Pediatrics, 32(5), 375–383. https://doi.org/10.1097/DBP.0b013e31821bd1dd -
Schuele, C. M. (2004). The impact of developmental speech and language impairments on the acquisition of literacy skills.Developmental Disabilities Research Reviews, 10(3), 176–183. https://doi.org/10.1002/mrdd.20014 -
Shriberg, L. D., Tomblin, J. B., & McSweeny, J. L. (1999). Prevalence of speech delay in 6-year-old children and comorbidity with language impairment.Journal of Speech, Language, and Hearing Research, 42(6), 1461–1481. https://doi.org/10.1044/jslhr.4206.1461 -
Sices, L., Taylor, H. G., Freebairn, L., Hansen, A., & Lewis, B. (2007). Relationship between speech-sound disorders and early literacy skills in preschool-age children: Impact of comorbid language impairment.Journal of Developmental & Behavioral Pediatrics, 28(6), 438–447. https://doi.org/10.1097/DBP.0b013e31811ff8ca -
Skebo, C. M., Lewis, B. A., Freebairn, L. A., Tag, J., Ciesla, A. A., & Stein, C. M. (2013). Reading skills of students with speech sound disorders at three stages of literacy development.Language, Speech, and Hearing Services in Schools, 44(4), 360–373. https://doi.org/10.1044/0161-1461(2013/12-0015) -
Snowling, M. J., Muter, V., & Carroll, J. (2007). Children at family risk of dyslexia: A follow-up in early adolescence.The Journal of Child Psychology and Psychiatry, 48(6), 609–618. https://doi.org/10.1111/j.1469-7610.2006.01725.x -
Sparrow, S. S., Cicchetti, D. V., & Balla, D. A. (2005). Vineland Adaptive Behavior Scales (2nd ed.). AGS. https://doi.org/10.1037/t15164-000 -
Squires, J., Potter, L., & Bricker, D. (1999). The ASQ user's guide.(2nd ed.). Brookes. -
Stevens, J. P. (2002). Applied multivariate statistics for the social sciences (4th ed.). Erlbaum. -
Storkel, H. L. (2006). Do children still pick and choose? The relationship between phonological knowledge and lexical acquisition beyond 50 words.Clinical Linguistics & Phonetics, 20(7–8), 523–529. https://doi.org/10.1080/02699200500266349 -
Thygesen, L. C., & Ersbøll, A. K. (2014). When the entire population is the sample: Strengths and limitations in register-based epidemiology.European Journal of Epidemiology, 29(8), 551–558. https://doi.org/10.1007/s10654-013-9873-0 -
Tuomi, S., & Ivanoff, P. (1977). Incidence of speech and hearing disorders among kindergarten and grade 1 children.Special Education in Canada, 51, 5–8. -
van Viersen, S., de Bree, E. H., Zee, M., Maassen, B., van der Leij, A., & de Jong, P. F. (2018). Pathways into literacy: The role of early oral language abilities and family risk for dyslexia.Psychological Science, 29(3), 418–428. https://doi.org/10.1177/0956797617736886 -
Wallace, I. F., Berkman, N. D., Watson, L. R., Coyne-Beasley, T., Wood, C. T., Cullen, K., & Lohr, K. N. (2015). Screening for speech and language delay in children 5 years old and younger: A systematic review.Pediatrics, 136(2), Article e448-462. https://doi.org/10.1542/peds.2014-3889 -
Wang, M. V., Lekhal, R., Aarø, L. E., & Schjølberg, S. (2014). Co-occurring development of early childhood communication and motor skills: Results from a population-based longitudinal study.Child: Care, Health and Development, 40(1), 77–84. https://doi.org/10.1111/cch.12003 -
Webster, R. I., & Shevell, M. I. (2004). Topical review: Neurobiology of specific language impairment.Journal of Child Neurology, 19(7), 471–481. https://doi.org/10.1177/08830738040190070101 -
Zambrana, I. M., Pons, F., Eadie, P., & Ystrom, E. (2014). Trajectories of language delay from age 3 to 5: Persistence, recovery and late onset.International Journal of Language & Communication Disorders, 49(3), 304–316. https://doi.org/10.1111/1460-6984.12073