Swahili speech development: Preliminary normative data from typically developing pre-school children in Tanzania

Abstract

Background Swahili is widely spoken in East Africa, but to date there are no culturally and linguistically appropriate materials available for speech-language therapists working in the region. The challenges are further exacerbated by the limited research available on the typical acquisition of Swahili phonology. Aim To describe the speech development of 24 typically developing first language Swahili-speaking children between the ages of 3;0 and 5;11 years in Dar es Salaam, Tanzania. Methods & Procedures A cross-sectional design was used with six groups of four children in 6-month age bands. Single-word speech samples were obtained from each child using a set of culturally appropriate pictures designed to elicit all consonants and vowels of Swahili. Each child's speech was audio-recorded and phonetically transcribed using International Phonetic Alphabet (IPA) conventions. Children's speech development is described in terms of (1) phonetic inventory, (2) syllable structure inventory, (3) phonological processes and (4) percentage consonants correct (PCC) and percentage vowels correct (PVC). Results & Outcomes Results suggest a gradual progression in the acquisition of speech sounds and syllables between the ages of 3;0 and 5;11 years. Vowel acquisition was completed and most of the consonants acquired by age 3;0. Fricatives/z, s, h/ were later acquired at 4 years and /θ/and /r/ were the last acquired consonants at age 5;11. Older children were able to produce speech sounds more accurately and had fewer phonological processes in their speech than younger children. Common phonological processes included lateralization and sound preference substitutions. Conclusions & Implications The study contributes a preliminary set of normative data on speech development of Swahili-speaking children. Findings are discussed in relation to theories of phonological development, and may be used as a basis for further normative studies with larger numbers of children and ultimately the development of a contextually relevant assessment of the phonology of Swahili-speaking children.