Describing mathematics classroom teaching and learning is part of a professional expertise. Comparing 'our distinct stories' and 'our professional languages' about teaching and learning in mathematics classes around the world, reveals cultural and linguistic underpinnings of our 'stories' and 'languages'. Analysing and understanding these 'stories' and 'languages' in the form of narratives of classroom lessons, is a methodological approach that allows us to study and compare language as a resource across different cultural and linguistic contexts. We based our approach on results of the Lexicon Project, which set out to document the terms and the professional vocabulary that teachers use for describing the phenomena of middle school mathematics classrooms around the world, but enlarged this approach by narratives and a narrative methodology. Our cultural comparative approach based on these narratives revealed not only technical terms that define and make explicit didactical intentions, techniques and approaches, but also offered narrative descriptions of the enactment of the didactic intentions and techniques in situ. This approach provides a deeper understanding of the potential of language and turned out to be valuable for understanding how language orients teachers' visions and analyses of mathematics classrooms.