The animation you assign to the Listening state plays when the user presses the push-to-talk hot key for speech input. Create and assign a short animation that makes the character look attentive. Similarly, define its Return animation to have a short duration so that the character plays its Hearing state animation when the user speaks. A Hearing state animation should also be brief, and designed to let the user know that the character is actively listening to what the user says. Head tilts or other slight gestures are appropriate. To provide natural variability, provide several Hearing state animations.