This cross-sectional study provides a language learning motivational profile of undergraduates from science, technology, engineering and mathematics (STEM) degrees taking language IWLP courses (language options open to all undergraduates) in a UK institution. Trends were generated through a questionnaire (363 participants) using self-determination theory. A comparison between motivations for students' main degrees and IWLP choice was established, followed by an exploration of group differences regarding language learning attitudes. Results found intrinsic orientations for degree specialism choice in contrast with more varied and utilitarian motives for IWLP. These utilitarian perceptions were accompanied by strong cultural curiosity and challenge-seeking attitudes. No perceived external pressures to take up languages were reported, indicating an agentive relationship with language learning. The value of languages for general employability in the context studied was confirmed despite perceptions of lower relevance for STEM-specific contexts. Group differences found relate to the value attached to specific languages for STEM, to the presence of an international outlook by nationality and to the perception of the value of foreign languages to enhance employability by gender. The effect of monolingualism is also explored and implications of the motivations identified for the curriculum are discussed, highlighting further areas of study.