My first thought was that this was pointing towards an epiphenomenal view of consciousness. But I think it's actually something more radical and more testable. Yvain, check me if I get this wrong, but I think you're saying that "our conscious verbal acts -- both internally and externally directed -- do not primarily cause our actions."

Here is an experiment to test this: have people perform some verbal act repeatedly, and see if it shifts their actions. This happens to be a well known motivational and behavior-alteration technique, beloved of football teams, political campaigns, governments, and religions, among other organizations. My impression is that it works to a point, but not consistently. Has anybody done a test of how catechisms, chants, and the like shape behavior?