© 2014 John Benjamins Publishing Company. This paper explores the role of iconicity in spoken language and other human communication systems. First, we concentrate on graphical and gestural communication and show how semantically motivated iconic signs play an important role in creating such communication systems from scratch. We then consider how iconic signs tend to become simplified and symbolic as the communication system matures and argue that this process is driven by repeated interactive use of the signs. We then consider evidence for iconicity at the level of the system in graphical communication and finally draw comparisons between iconicity in graphical and gestural communication systems and in spoken language.