Recent observations of emerging languages indicate that human language can develop rapidly within a decade or two. However, the underlying mechanisms driving the rapid emergence of a language remain unclear. In this presentation, I will discuss a line of research focusing on a key starting point of language creation: individuals’ creation of communicative symbols. We investigated this symbol creation process by asking hearing participants to create a silent gesture for a concept within four seconds. Specifically, we explored how communicative efficacy (the ease with which interpreters understood the gestures), production cost (the effort required to conceptualize and produce the gestures), and individuals’ socio-cognitive abilities influence this process. Our findings showed that people tended to produce communicatively efficient gestures, that is, the majority of participants produced gestures that were effective for comprehension. Furthermore, more empathetic participants estimated gestures’ communicative efficacy more accurately and produced gestures with higher communicative efficacy, indicating that they considered how recipients might interpret the gestures when deciding what to produce. Participants also tended to create gestures with lower production costs. These results suggest that humans can create a communicatively efficient symbol for a concept within seconds, which may partly explain how a new language can emerge quickly within a community.