My hypothesis is that there is symbolic communication at homo habilis and the origin of the Stone Age, 2.5 million years ago ; Not articulate speech but singing , whistling , clicking . music with instruments ( among first tools) , dance, drawing ; because it defines us, genus Homo

http://take10charles.blogspot.com/2021/09/origin-of-language-human-dancer_27.html

http://take10charles.blogspot.com/2022/01/only-humans-have-symbolic-communication.html

http://take10charles.blogspot.com/2022/03/several-hypotheses-on-human-evolution.html

Culture -custom is symbolically constituted behavior :

http://take10charles.blogspot.com/2021/12/anthropological-definition-of-culture.html

http://take10charles.blogspot.com/2022/04/he-need-to-convey-information-using.html