All around the world, people of different cultural and linguistic backgrounds add to verbal language with gestures that communicate tone and emotion. But while some level of minor gestural communication is common, it’s incredibly rare for verbal societies to use visual language to communicate information that’s central to a conversation. In fact, for many years, linguists believed that, outside of hearing impaired communities, the use of visual language was essentially non-existent. As it turns out, that may be far from the case.

A recent study published in the journal Language [PDF] found that Northwestern Amazonian speakers of Nheengatú use gestures to describe time. Rather than use a numerical system, Nheengatú speakers talk about time by pointing at where the sun would be in the sky at a specific time of day. For instance, instead of saying “eight o’ clock,” Nheengatú speakers gesture towards the sky, seamlessly incorporating visual language into a predominantly verbal framework.

The Linguistic Society of America press statement [PDF] explains, “When humans conceive of grammar we might think of categories like nouns, verbs, adjectives and adverbs that people communicate by vocalizing. Research with speakers of Nheengatú reveals that this is not always the case, however, and that in some languages it is possible to communicate some of these concepts, by combining movements of the hands and body with speech in systematic ways.”

Researchers believe that Nheengatú time telling is just the tip of the iceberg in terms of combined visual and verbal communication. While many previous linguistic studies have utilized written and audio recordings, which make the study of visual language impossible, future studies using video recordings or active fieldwork could uncover new combinations of visual and spoken language.