Dominant research evaluation systems potentially lead to a homogenization of research. A focus on the total number of citations or journal impact factors can motivate researchers in non-English contexts to publish in English only. Efforts to publish in languages other than English run the risk of becoming ‘lost science’. The purpose of this article is to offer an indicator, the PLOTE-index, which measures the percentage of citations flowing from the non-English publications of a researcher or a group of researchers. If the spread of citations over language areas is measured, it becomes visible. Only then can it be analyzed, debated, and evaluated. In a feasibility study, PLOTE scores are calculated for 40 professors in political science in Denmark. The relation between the PLOTE-index and total number of citations is discussed. Variations across subfields are demonstrated and discussed, as well as a decline in PLOTE scores over time. The potential use of the PLOTE-index in research policy, research evaluation, strategy-making, and recruitment is discussed, as well as future developments of the index.