The interaction between student language use and sensemaking is an area in science learning that needs further elucidation in order to meet government standards in science education. In this study, concept mapping was used to explore the relationship between scientific language use and sensemaking defined as the interaction between the scientific concept system and everyday concepts in order to make sense of a proposed phenomenon. Eighty-eight concept maps from five different school classes and two school systems were analyzed in terms of their language use and concept formation from a Vygotskian perspective. This work proposes an intimate relationship between student language use, concept system formation and sensemaking in science, indicating possible implications for the study of learning as well as formative assessment using concept maps.