Teachers in classrooms use a vast of array of language to support children in their educational development. Previous research with teachers and children in secondary schools has identified that, when supporting children to prepare for important tests, teachers use supportive statements as well as statements stressing the negative outcomes associated with poor performance. However, in the primary school context, research has not identified the specific language that is being used by teachers for test preparation. In this explorative mixed methods study, eight teachers completed communication diaries and were interviewed to identify the types of communication they were using in the classroom towards children aged 6-11 in order to support their test preparations. Two focus groups were also held with children to determine their awareness of teachers' communicative messages. The final phase of the study gathered data from a questionnaire distributed to a large sample of 112 primary school teachers allowing broader exploration of test-related language use in the classroom. Results identified various forms of communication being used by primary school teachers when preparing children for important tests, with children also aware of these statements. This included informative communication about test arrangements, outcome based statements, efficacious statements, reassuring and calming messages, language statements that related to the importance of tests, and test reminders. The findings further suggested that efficacious communication was the most frequent form of communication that was employed in primary classrooms, though use of language varied amongst teachers. Furthermore, the research identified that teachers were combining particular forms of communication, and it is likely that this communication fluctuated over the academic year. Teachers were also judicious in their use of communication towards children, where statements were chosen to have maximum effect on children based on teachers' assessments of children's characteristics. Additional factors such as teacher control, teacher philosophy, a view of children as dependent, views about testing, and teacher-held beliefs about particular forms of communication were also explored to judge their impact on the language used by teachers. The findings of this study provide a preliminary foundation for future research to explore teacher communication and its effects on children's test preparations in primary schools.