The theory rests on another idea that many people assume is obviously true without ever thinking twice.
It's the notion that verbal thought and verbal thinking is required and fundamental part of consciousness and self awareness.
When I started to read about the philosophy of consciousness, it became obvious that most people experience their own consciousness differently than I do. Their inner starting point is completely off from my personal epistemology and it may be hard for them to see the alternative viewpoint interesting.
For me, verbal thoughts have always been just one cognitive ability in par with spatial reasoning. I have always had trouble understanding why people link verbal thinking and consciousness and self awareness.
Temple Grandin's has really good insight into the differences of thinking: Thinking the Way Animals Do: Unique insights from a person with a singular understanding http://www.grandin.com/references/thinking.animals.html