Muse

When muse is enabled, the software will automatically vocalize periodically.

In the films, R2 is often seen talking absentmindedly to himself. These musings have a unique vocal character which is distinctly different from R2's responses to stimuli. Musings are often more subdued. This makes sense, as we don't mutter to ourselves with the same purpose or energy that we use when speaking to someone else or when reacting to a stimulus.

Muse is not to be confused with a crude "randomizer," nor is it a substitute for manually triggered stimuli.