About 8–9% of children aged between 5 and 8 years of age have speech sound disorders [1, 2] which affect their ability to communicate. Prevalence figures specific to countries in Africa are lacking, but it is likely that they are similar to the ones noted here.

Speech sound difficulties may be linked to developmental days, cleft-lip and palate, childhood apraxia of speech, and hearing impairment, but for many children such difficulties are idiopathic: we do not know what causes them. What we do know is that speech sound difficulties left untreated may have negative academic and psychosocial consequences for children and families.

Our research into speech sound disorders has three main themes:

  1. Typical speech development of children acquiring African languages.

Ongoing projects describe the typical phonological development of some of the Bantu languages spoken in Southern and East Africa. These include isiXhosa [3-6], isiZulu [7], Setswana [8], and Swahili [9]. A further strand of research focuses on the acquisition of South African English [10-12].

  • Interventions and frameworks for understanding the nature of speech difficulties;

Psycholinguistic models have been widely used in studies focusing on speech and language difficulties in adults with acquired neurogenic communication difficulties. We are interested in the application of these frameworks to children’s speech and literacy development and the difficulties children may experience. Projects in this area focus on intervention for bilingual children acquiring isiXhosa and English [4,5], intelligibility [13] and children with cochlear implants in the multilingual context of South Africa [14]. Further information about psycholinguistic approaches to children’s speech difficulties can be found here [15,16]. 

  • Development of resources to support speech and language therapists

Research is needed to develop tools that will enable speech-language therapists to provide equitable, ethical and evidence-based care. Speech assessments used are not always appropriate for the populations with which they are used. The International Expert Panel on Multilingual Children’s Speech hcalls for us to:

“…generate and share knowledge, resources, and evidence to facilitate the understanding of cultural and linguistic diversity that will support multilingual children’s speech acquisition”. 

“…acknowledge and respect [children’s] existing competencies, cultural heritage, and histories… assessment and intervention should be based on the best available evidence.”

Child Language Africa responds to this call through our ongoing work adapting existing speech assessments [17], developing new assessments of children’s speech [3,7–9] and evaluating available resources and interventions.


  1. Law, J., Boyle, J., Harris, F., Harkness, A., & Nye, C. (2000). Prevalence and natural history of primary speech and language delay: Findings from a systematic review of the literature. International Journal of Language and Communication Disorders35, 165-188.
  2. 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 research42(6), 1461-1481.
  3. Maphalala, Z., Pascoe, M. & Smouse, M. (2014). Phonological development of first language isiXhosa-speaking children aged 3;0- 6;0 years: A descriptive cross-sectional study. Clinical Linguistics and Phonetics, 28 (3), 176–194.
  4. Pascoe, M., Rossouw, K. & Mahura, O. (2018). Core vocabulary intervention for an isiXhosa-English speaking child with speech sound difficulties. Southern African Linguistics and Applied Language Studies https://doi.org/10.2989/16073614.2018.1548292
  5. Rossouw, K. & Pascoe, M. (2018). Intervention for bilingual speech sound disorders: Description of an isiXhosa-English speaking child. South African Journal of Communication Disorders, 65(1), a566. https://doi. org/10.4102/sajcd.v65i1.566
  6. Pascoe, M. & Smouse, M. (2012).  Masithethe: Speech and language development and difficulties in isiXhosa.  S Afr Med J 102(6): 469–471.
  7. Pascoe, M., Jeggo, Z. (2019). Speech acquisition in monolingual children acquiring isiZulu in rural KwaZulu-Natal, South Africa. International Journal of Monolingual and Bilingual Speech (in press).
  8. Mahura, O. & Pascoe, M. (2016). The acquisition of Setswana segmental phonology in children aged 3;0 – 6;0 years: A cross-sectional study. International Journal of Speech Language Pathology http://dx.doi.org/10.3109/17549507.2015.1126639
  9. Gangji, N., Pascoe, M. & Smouse, M. (2015). Swahili Speech Development: Preliminary normative data from typically developing pre-school children in Tanzania. International Journal of Language and Communication Disorders, 50(2), 151–164.
  10. Pascoe, M., Mahura, O. & Le Roux, J. (2018). South African English speech development: Preliminary data from typically developing pre-school children in Cape Town. Clinical Linguistics and Phonetics, 10.1080/02699206.2018.1510985.
  11. Pascoe, M., Mahura, O., Le Roux, J., Danvers, E., de Jager, A., Esterhuizen, N., Naidoo, C., Reynders, J., Senior, S. & van der Merwe, A. (2018). Speech Development in Three-year-old Children Acquiring isiXhosa and English in South Africa. Chapter in Babatsouli, E., Ingram, D. & Muller, N. (Eds). Crosslinguistic Encounters in Language Acquisition: Typical and Atypical Development. Multilingual Matters, Bristol. 
  12. Pascoe, M. & Mahura, O. (2017). Acquisition of South African English by three- to five-year-old children in Cape Town. In E. Babatsouli (ed.), Proceedings of the International Symposium on Monolingual and Bilingual Speech 2017 (pp. 234–240). ISBN: 978-618-82351-1-3. URL: http://ismbs.eu/publications-2017
  13. Speake, J., Stackhouse, M. and Pascoe, M. (2012). Vowel Targeted Intervention for Children with Persisting Speech Difficulties: Impact on Intelligibility.  Child Language Teaching and Therapy, 28(3), 277–295.
  14. Pascoe, M., Randall-Pieterse, C & Geiger, M. (2013). Speech and literacy development in a child with a cochlear implant: Application of a psycholinguistic framework. Child Language Teaching and Therapy, 29 (2), 185–200.
  15. Pascoe, M., Stackhouse, J. & Wells, B. (2006). Persisting Speech Difficulties in Children. (Book 3 in Children’s Speech and Literacy Difficulties Series). Wiley and Sons Ltd.: London.  
  16. Pascoe, M., Stackhouse, J. & Wells, B. (2005).  Phonological Therapy within a Psycholinguistic Framework: Promoting Change in a Child with Persisting Speech Difficulties. International Journal of Language and Communication Disorders, 40 (2), 189–220.
  17. Pascoe, M. & McLeod, S. (2016). Cross-Cultural Adaptation of the Intelligibility in Context Scale for South Africa. Child Language Teaching and Therapy 32(3), 327–343. DOI: 10.1177/0265659016638395.