Support for children with special educational needs in inclusive classrooms is increasingly provided by teaching assistants (TAs). They often have a direct pedagogical role, taking responsibility for instruction in mathematics. The quality of TAs' oral skills is crucial for learning but has rarely been researched. Using conversation analysis, this study compares teacher and TA talk in terms of turn allocation, topic generation and repair. From 130 recordings, transcripts of mathematics teaching in four lessons were analysed in depth. We found that teachers "open up" students whilst TAs "close down" the talk. Teachers, with whole classes, adopt inclusive teaching strategies to ensure oral participation whereas TAs, working with individuals, emphasise task completion. Teachers use open strategies for topic generation whilst TAs ask closed questions. Teachers withhold correction with prompts and hints whilst TAs supply answers. The findings are interpreted with reference to the TA role and implications for management and training. (Contains 2 tables.)