Concept-based language instruction (C-BLI) is a pedagogy guided by sociocultural theory, which has been shown to be effective in facilitating second language learning. Typical activities include materialization by using a schema for a complete orienting basis of an action (SCOBA) and languaging, through which learners' internalization of scientific knowledge can be observed. However, previous studies have mainly used languaging as an assessment tool to examine the outcome of the internalization of concepts. Few studies have integrated SCOBAs (visual) and languaging (oral or written) in their investigation of the internalization process. This 5-week study involved 53 Chinese English-as-a-foreign-language learners in a university who were all taught with the C-BLI approach to learn English modal verbs. Among them, there were 26 lower proficiency students and 27 higher proficiency students. Visual, oral, and written data were collected to examine the participants' internalization of the modal verb concepts. All 53 learners participated in SCOBA drawing and written-languaging tasks. Twelve students (6 per group) volunteered to participate in oral languaging. The results showed that in the SCOBA drawing activity, higher level learners produced more abstract, systematic, and imitated visualizations of the concepts, while lower level learners produced more concrete, disconnected, and emulated visualizations. With regard to oral languaging, both groups largely abandoned their previously learned "rule of thumb" after the C-BLI intervention, and there were no obvious differences in oral-languaging performance between the two groups, except that the higher group produced more languaging units. Finally, we also found that the changes between pre- and post-written-languaging tasks for lower level students were more obvious, especially in the appropriation of SCOBAs in written languaging.