Phonetic Factors Affecting the Early Acquisition of Fricative and Affricate Consonants in Setswana

This article focuses on the early acquisition of fricative and affricate consonants in Setswana, a Bantu language spoken in Botswana and South Africa (Tswana S30). We describe a series of intriguing patterns displayed in the speech of Setswana-learning children between the ages of 1 and 3 years. The data display clear trends also expected from the larger literature on phonological and phonetic development, including the stopping, affrication and debuccalization of target fricatives |s, ʃ, f, χ|, and the simplification (deaffrication; deaspiration) of target affricates |tɫ, tɫʰ, ʦ, ʦʰ, ʧ, ʧʰ, ʤ|. Beyond these general trends, the data reveal intriguing asymmetries: (a) the fact that coronal fricatives |s/ʃ| display much less debuccalization to laryngeals than the non-coronal fricatives |f, χ|; (b) the observation that while the non-lateral affricates |ʦ, ʦʰ, tʃ, ʧʰ, ʤ| are generally produced with their target place of articulation, the lateral affricates |tɫ, tɫʰ| can be variably substituted for velar stops [k, kʰ] instead. We first discuss why an analysis of the observations stated above transcends traditional models of phonology based on phonological features. We then argue that, in addition to phonological conditioning, issues in speech phonetics may also influence how children analyze the speech forms of their language. Our analyses reconcile the data with phonological theory, also in ways that offer additional insight on the origins of speech sound substitutions in child language.