Abstract
Teachers Cognitive Academic Language Proficiency (CALP) has been found to be important for meaningful teaching and learning of any subject. Over the years research has focused more on English second language learners' CALP needs and less on the teachers. Because teachers are the cornerstones who drive the process of teaching and learning in the classrooms, their proficiency in the language of teaching and learning are vital. In the South African context, English is regarded as the official language of teaching and learning from grade 4 onwards despite that both teachers and learners come from diverse linguistic backgrounds where English is a second or third language. Underpinned by the socio-cultural theory as the theoretical framework, the paper reports on a study that determined both in-service and pre-service teachers' perceived CALP needs when teaching Natural Sciences in multicultural township schools. In a qualitative research approach 12 teachers were randomly selected who comprised of six in-service teachers and six final year pre-service teachers enrolled for a Natural Sciences course at a University in South Africa. Each teacher was interviewed once using a semi-structured interview schedule which allowed them to freely express their perceived CALP needs. The data was analysed using a constant comparative method. Findings from the analysis of data showed that teachers experienced many challenges when teaching Natural Sciences using English, a language different from their home languages and those of their learners. They indicated that because science is a unique language on its own they struggle to spell, pronounce, understand and most importantly to explain to the learners using English. The teachers indicated their little to non-exposure to English other than in the classrooms compared to their home languages. Whilst some of the teachers perceived English as an important language due to its universality, they however indicated that code switching to own home language and those of the learners was inevitable when it comes to meaningfully explain some scientific concepts and processes in a way that learners would comprehend. However, others acknowledged the challenges of using code switching in the linguistic diverse classroom environments. Most teachers suggested training workshops intended to develop them with skills to identify appropriate terms and expressions, and explain complex scientific concepts in English. These findings have implications on both pre-service and in-service teacher professional development programmes.