This paper reports research designed to highlight how three groups of teachers make sense of linguistic, ethnic and cultural diversity in the classroom. The collecting of the data concentrated on the way in which the participants in the study worked together to construct socially negotiated meanings of linguistic diversity within the context of language learning, principally in the EFL (English as a Foreign Language) classroom. A key assumption of the analysis is that the speakers within a conversation "construct" or "assemble" categories which are based on a background of "common knowledge", and that the assembly of categories are not descriptions of truth; rather they are the speakers' constructed versions of how they make sense of the world. The research indicated that the participants in this study consistently assembled the category of "diversity" with features such as "problematic", "difficult", "hard"; thus implying that there was a common understanding of this type of classroom. However, the analysis indicates that, despite an overall similarity among the groups' categorisations concerning linguistic diversity, the preservice teachers were more likely to re-negotiate their initial categories towards more positive understandings of linguistic diversity. Details of the approach, examples of the analysis and a discussion of the research findings are provided.