We regularly compare magnitudes and describe these comparisons to other people. This article reports 9 experiments that examine how messages about the relative magnitude of two items affect inferences about the items’ spatial arrangement. Native English speakers were given sentences such as “One tree is taller than the other,” and their beliefs about the left–right arrangement of the objects were probed. Across a wide range of dimensions and tasks, the choice of comparative shaped spatial inference: “Smaller” comparatives (e.g., shorter, lighter, less) led to the belief that the small item was on the left, whereas “larger” comparatives (e.g., longer, heavier, more) led to the belief that the small item was on the right. These inferences match the tendency of message senders to choose comparatives based on spatial layout, such that purely ordinal magnitude comparisons communicate information about the spatial arrangement of the compared objects. There was also evidence for a canonical “small–large” inference, consistent with the tendency of English speakers to associate “small” with “left” and “large” with “right”; however, this effect was task-dependent, indicating a flexible, language-based mapping rather than an immutable bias. Finally, there was evidence that the choice of comparative influenced the salience of particular response options. These results help to elucidate the deep interconnections between language, space, and magnitude: Linguistic tokens and structures reflect physical reality and, in turn, shape mental representations of the physical world.