The paper will explore language associated with the value of rationalism, regarded as a crucial value in learning mathematics. Logical connectives are one set of words and phrases used for reasoning and explanation that are fundamental rational processes in mathematics. However, little or no emphasis is given in the teaching of mathematics to such language, at least in Victoria, Australia, and probably in many other parts of the world. Indeed with the increased use of manipulatives in teaching mathematics in primary classrooms, it is likely that the teaching of descriptive language has increased in such an environment, but with little proactive teaching of language needed for explanations. Hence, there is potentially a dilemma for teachers and students in not having a shared language to embrace this fundamental value of mathematics.