Another proposal involving natural sounds was nicknamed the “yo-he-ho” theory.
The idea is that the sounds of a person involved in physical effort could be the source of our language, especially when that physical effort involved several people and the interaction had to be coordinated.
The appeal of this proposal is that it places the development of human language in a social context.
Groups are necessarily social organizations and, to maintain those organizations, some form of communication is required, even if it is just grunts and curses.
This is an important idea involving the uses of humanly produced sounds. It does not, however, reveal the origins of the sounds produced.