Phonological and morphological structures are an important level of language organization that is widely investigated in humans and has been documented not only in speech but also in signs. Comparatively less is known about the presence of these structures in non-human animal communication systems. Specifically, although phonology and morphology both seem to be present in the vocalizations of some avian and primate species, no study to date has investigated the presence of these structures in non-human visual communication. It is therefore the main aim of this project to perform the first phonological and morphological analysis of primate gestural communication. To do so, we will investigate one of our closest living relatives, the chimpanzee.

This main aim unfolds into the following specific objectives:

1. To provide a comprehensive formal description of the chimpanzee gestural repertoire
2. To identify the core meanings of chimpanzee gesture forms
3. To document the presence of minimal pairs and morpheme-like structures across the chimpanzee gestural repertoire
4. To provide evidence of phonological and morphological structures in non-human visual communication

In this study, we will first identify candidate substructural components of chimpanzee gestures by describing their formal parameters across the repertoire. Second, we will determine the core meanings of gestures through the application of a novel framework for the comprehensive study of meaning in animal signals. Subsequently, the identified candidate components (i.e. the formal features of gestures) will be tested as phoneme-like structures by looking for minimal pairs in the gestural repertoire (i.e. pairs of gestures that differ in their meaning but differ in their form by just one single parameter). Moreover, we will assess whether some of these parameters are rather meaningful and inflect the meaning of gestures by combining with them, akin to morphemes.