It was actually about people who reported having no inner-monologue in their day to day life. IE, they don't think about what they are doing and what they are going to do in terms of language. The notion is that while they know and cay speak/understand language, for some reason it doesn't become their primary mode of thinking like it does for most people. There was a PBS article a while back about some people who were deaf and grew up without ever learning language and then one of them learns language one day and he explains that he doesn't really know how to describe anything from before the shift... sort of like the plot of Baby Geniuses, only all the babies are a little retarded.