Humans (Homo sapiens) are the most abundant and widespread species of primates, characterized by bipedality and large, complex brains enabling the development of advanced tools, culture and language.

Some scholars assume the development of primitive language-like systems (proto-language) as early as Homo habilis, while others place the development of symbolic communication only with Homo erectus (1.8 million years ago) or with Homo heidelbergensis (0.6 million years ago) and the development of language proper with...