One of the things that distinguishes humans from other life forms we know of is the ability to have complicated conversations. We use body language, of course, but we mostly use our voice. Voice is extremely important to us as a species; it gives us the ability to exchange ideas in a very concise way.
People are so good at distinguishing voices that even when the sounds are distorted we still can make out the intent of what is being said. A great example of this is the weird phenomenon of people who play music backward to find a hidden message. The fact that they actually do find something there say a little about the recording artists but a lot about our ability to hear meaningful sounds in almost anything. The human mind is a powerful thing. So, it would be great to use that in our apps as well. Fortunately, we can. Which is what this chapter is...
