Philosophiae Doctor - PhD / This thesis examined the difficulties experienced by Grade 6 isiXhosa-speaking learners in learning Natural Science through English as the medium of instruction at a primary school in the Western Cape. In 1994, South Africa became a democratic country where people were given the right to choose the language of learning and communication (Constitution of the Republic of South Africa, 1996). The assumption made in relation to the right to language was that this would provide equal opportunities and equal access to education for all learners. All learners would then be able to attain academic success. The study was pursued against the backdrop of the serious academic underachievement of African learners at schools around the country (often culminating in high matric failure rates), particularly in mathematics, science and technology (Probyn, 2005; Cleghorn, 2005; Taylor & Vinjevold, 1999). Following a mixed-method approach (involving both qualitative and quantitative research methods), within the constructivist paradigm, the study examined the various factors which act as barriers to learning and contribute to difficulties in learning Natural Science by Grade 6 isiXhosa-speaking learners in one school in the Western Cape. It also examined the coping strategies used in dealing with the barriers by both the learners and educators in order to address the learning difficulties. The study was conducted over a period of four months, spread over two years (2008 and 2009), in the Metropole Central Education District (MCED) of the Western Cape. The following participants were involved in the study: 205 Grade 6 learners (103 learners in 2008 and 102learners in 2009), 4 Natural Science educators (including 2 HODs), 1 principal, and 4 parents. The focus of the study was, however, on 26 isiXhosa-speaking learners (13 learners from each year in 2008 and 2009). The data were collected using the following research methods: questionnaires, classroom observation, document analysis, and interviews. The data were analysed through content analysis and (analysis of) language usage (including sentence construction), and were interpreted with respect to the study's research questions. The findings of the research revealed that language (including both the English language of learning and teaching or LOLT, and the language of science) was a major barrier to the learning of Natural Science by Grade 6 isiXhosa-speaking learners. The language barrier was exacerbated by factors within the teaching and learning context, the school environment, as well as by social factors in the learners' own home backgrounds. On the basis of the findings of the research and the related literature, the study makes recommendations regarding what could be done to address the difficulties, as well as proposals for future research. The key recommendations include: • Introducing a more flexible bilingual education policy to enable additive bilingualism to be practised by both learners and educators; • Compiling a list or glossary of words, concepts and terms that matter in Natural Science and ensuring that the learners fully understand their meaning and use them appropriately; • Educators constantly reflecting on their own teaching styles and practices in relation to their effectiveness and impact on their learners; • Educators constantly considering 'different and creative ways' of assessing learners for whom the English LOLT is not a home language; and • District Offices providing systemic support for schools and creating an enabling learning environment.