As part of a larger project focused on decolonising mathematics education for Aboriginal students in Atlantic Canada, this article reports on the role of the Mi'kmaw language in mathematics teaching. By exploring how mathematical concepts are talked about (or not talked about) in the Mi'kmaw language, teachers and researchers can gain insight into how Mi'kmaw children think about mathematical concepts. It is argued that much can be learned by asking questions such as "What's the word for... ?" or "Is there a word for... ?" Numerous examples of such conversations are presented. It is argued that particular complexities arise when words such as "flat" and "middle" are taken-for-granted as shared, but in fact do not have common use in the Mi'kmaw language. By understanding these complexities and being aware of the potential challenges for Mi'kmaw learners, teachers can better meet the needs of these students. It is argued that understanding Aboriginal languages can provide valuable insight to support Aboriginal learners in mathematics.