ABSTRACT The purpose of this research was to discover the value of ‘deep’ talk in developing Cognitive Academic Language Proficiency (CALP), with primary focus on a group of ‘under-prepared’ first year university students for whom English is an additional language (EAL), who were registered for an ‘extended degree’ in the Faculty of Humanities at the University of Johannesburg, Kingsway campus. The method of research was qualitative and took the form of a teaching intervention in which groups of students voluntarily participated in the performance of different learning activities (such as reading, talking and writing) either as individuals of as members of a group. All of the students were given identical background texts to read. The texts provided contextual information on a topic pertaining to a gender debate. Some students read the texts prior to participating in a discussion on the topic, after which they wrote an argumentative essay. Other students talked about the topic first, and then read the texts before writing their essay. A ‘control’ group of students did not talk at all, but just read the texts and then wrote an essay on the topic. The researcher analysed transcriptions of tape-recordings of the group discussions, using limited discourse analysis to highlight various ‘speech acts’ to assess how the students used language to actively engage with each other and build their arguments. The research findings were also assisted by an analysis of the essays and reflections written by each student. The research found that the process of talk itself in which the students used language to respond to each other’s ideas, helped to cognitively challenge the students in the development of their arguments. The research also found that the cognitive development gained through the talk was helpful in assisting students to formulate their written arguments in their essay. The research found that some contextual support in the form of background readings was also helpful. The order in which this took place was also found to be important. The research found it to be particularly useful for students to be given background reading before their talk, rather than after their talk, as this gave students a more informed perspective with which to approach their group discussion. By examining the essays in relation to the transcripts of the talk, the researcher explored the extent to which a more informed perspective on the topic, coupled with the way in which students used language, helped students to develop a more balanced approach in developing their written arguments.