Some of the best material on language and its influence on human development can be found in a number of documentaries on the subject of human evolution:
The Day We Learned To Think (BBC – Horizon – 2003)
[Key segment: 2:27 – 7:57]
There are also some great key points about language in a 2008 documentary: Clash Of The Cavemen (History Channel). Here is but one example:
Another valuable documentary with key points about language is Neanderthals On Trial (NOVA PBS Documentary) [aired January 22, 2002].
This documentary (aired August 31, 2011) Becoming Human (Episode 3) – Last Human Standing contains much more details about discoveries in South Africa.
Evolution – The Mind’s Big Bang (PBS Documentary)
One of the key concepts in the above video [time: 23:54 – 25:20] is the creation of a CULTURAL ENTITY as distinctly unique to human species.
Another great reference video is this lecture that illuminates the construct of ancient civilizations as members in a global cultural and economical network which at one point collapsed leading to the collapse of various ancient civilizations in connection to the network. This connects well to the concept of a social neural network and the idea that communication serves as a catalyst for the development of consciousness:
Key reference book: “The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World” by David W. Anthony