The genesis of inner speech: forward models or constructive imagination?

Inner speech is often said to be a by-product of motor control, the product of a forward model driven by an efference copy of a cancelled motor command to speak. The conscious auditory imagery of inner speech is said to arise when the product of this forward model becomes conscious. This conception of the genesis of inner speech founders on some basic questions about the consciousness of inner speech and about the interaction between inner speech and episodes of imagination. Further, the empirical evidence cited in support of this theory falls short. An alternative starts with a general conception of constructive imagination, which is our capacity to produce mental images (visual, auditory, etc.) in the course of practical problem-solving. Inner speech may be conceived as a species of constructive imagination in which we construct auditory images of episodes of speech. Inner speech is an imaginative representation of speech events that do not exist, which also represents the objects and events that the represented episodes of speech would represent if they existed.