This multiple case study investigated how college students with diverse ethno-linguistic backgrounds used chemistry vocabulary as a way to look at their discursive identities and cultural border crossings during first semester general chemistry laboratories. The data were collected in two major forms: video-taped laboratory observations and audio-recorded interviews. All transcribed data from videos and interviews were analyzed qualitatively, using the constant comparative method. Our results indicate that (1) participants explained the laboratories using vocabulary emphasized in both lecture and the laboratory; (2) participants were able to appropriate the scientific meanings of Dual Meaning Vocabulary (DMV) and Cross Meaning Vocabulary (CMV) into their discursive identities; (3) participants' prior English learning experiences and the classroom culture shaped their appropriation of scientific vocabulary and (4) participants' appropriation of chemistry language was deeply related to how they incorporated scientific culture into their everyday culture. These themes are discussed in depth using the cultural anthropological theoretical framework, the discursive identity lens, and a tiered definition of scientific vocabulary. Implications of this study are also discussed in terms of instruction and future research.