The evolution of arm-leg relationships presents something of a problem for embodied cognitive science. The affordances of habitual bipedalism and upright posture make our two sets of appendages and their interrelationships distinctively human, but these relations are largely neglected in evolutionary accounts of embodied cognition. Using a mixture of methods from historical linguistics, Cognitive Linguistics and linguistic anthropology to analyze data from languages around the world, this paper identifies a robust, dynamic set of part-whole relations that emerge across the human waistline between upper and lower appendage sets cross-culturally. The general pattern—identified as “arm-leg syncretism”—provides a plausible primary source for the uniquely human penchant for creative analogy, or “double-scope conceptual blending”, said to underlie the human language faculty (Fauconnier and Turner 2002, 2008; Deely 2002; Anttila 2003; Bybee 2010). This account not only addresses a conspicuous gap in the literature but also enables us to better understand what it means to be human—including how we came to be unique among other species and how we are still vitally interrelated with other species. Deely (2010) blends both sides of this tension into a single phrase: “the semiotic animal”. The paper further develops this distinction by drawing attention to one of the roles upright posture played in the emergence of semiotic consciousness.