The book is highly controversial. If it were fiction it would outsell The Da Vinci Code. It is written in a popular style and is readily understandable by anyone of any nationality with sufficient general education to make his or her way in the modern world. The only jargon is explained as the ideas are developed, for instance "Lithic", the Stone Age language roots the author claims to have discovered concealed like flies in amber in the lexicon of language today, and "psychosemantic trees" showing the descent of meanings from the original Stone Age elements of speaking, traced backwards in a manner similar to triangulation in survey. Hominids spoke, six hundred thousands years ago; and had tamed fire by then and had hearths at the mouths of their caves long before ash traces have been found. Meanings were originally attributed to single phonemes (roughly letters) as our bare bottomed forebears learned to pronounce them. Words were compiled as strings of them. Freud's psychological output can now be seen to be fanciful. But the sexual patterning of our earliest perceptions can still be traced underlying the wording of languages around the world today, probably all of them.
www.ontheoriginsofspeaking.com.