Yes, you are supporting both sides of the brain when you speak your Image Stream out loud. The expressing and receiving process is what's important.
Win Wenger says in the course that without a listener there generally isn't enough support for either side of the brain's neural circuitry. The act of describing, and the feedback from your output, develops conscious awareness of your inner images.
The important part of speaking aloud is having that external focus, whether it's a live person, tape recorder, or an imaginary friend. By speaking aloud to a listener the appropriate level of response will occur in your brain. It's in the way you hear your own voice and the words that you say that provides the feedback you need to guide you to the important information.
