This thesis provides a literature review on various topics related to the aims of the research project. In the process of sketching the rationale of this study, the language-in-education policy (LiEP) of South Africa is examined. The reasons why this policy is not successful, is discussed. Emanating from this discussion, the low literacy scores amongst young learners in South Africa are described and possible reasons for this occurrence are cited (Howie, Van Staden, Tshele, Dowse, & Zimmerman, 2012). The hypothesis that perceptual and articulation training of the vowels of English would enhance young English second language (Setswana first language-speaking) learners? awareness of English vowels, is posited and defended by referring to previous research (Moats, 2007; Trehearne, 2011; Seeff-Gabriel, 2003). In addition, it is stated that increased knowledge of the vowel system of English will improve English second language (EL2) learners? literacy skills (Moats, 2007). In order to explain and discuss the results of the investigations into the literacy skills of the EL2 learners participating in this study, the notions of literacy acquisition, phonological awareness skills, and language acquisition and language learning are examined. The main aim of this study is to assess the effects of intervention on the auditory perception and articulatory skills of English second language-speaking (EL2) (Setswana L1-speaking) learners in Grade 3, in the production of the monophthongs and diphthongs of the standard variety of South African English, namely White South African English (WSAfE) (Bekker, 2009). The effects are determined by acoustically comparing the vowel spaces of the participants before and after intervention. Therefore, a discussion of acoustic concepts such as the vowel space and the parameters thereof are provided. In addition, the vowels of WSAfE, those of Black South African English (BSAE), and the vowels of Setswana are discussed and compared according to their acoustic features. The results of this quasi-experimental, comparative study indicate that the vowel spaces of the EL1 and EL2 participants differ markedly before intervention, especially when comparing those of the short and long monophthongs of English. After intervention, the vowel spaces of especially the Experimental group are seen to approximate those of the EL1 participants in the Norm group. Interesting findings concerning the central schwa vowels and the diphthongs were made. These indicate that young EL2 (Setswana L1-speaking) learners do not use BSAE, but use a new? variety of English that is closer to WSAfE (Mesthrie, 2008). Pertaining to the measurable sub-aims of this study, the phonological awareness skills and literacy skills of the participants are assessed and compared, before and after intervention. The improvement of the phonological awareness skills and literacy skills of the Experimental group, as well as the changes in the vowel spaces that are noted for this group, prove the hypothesis that intervention in the form of additional input concerning the English vowels will enhance second language learners? perception and articulation. This strengthens the opinion that second language learners need quality teaching of the sound system of the language of learning and teaching. / Thesis (DPhil)--University of Pretoria, 2016. / African Languages / DPhil / Unrestricted