Learn in the textbookFundamentals of Interface Design and Input Operations
DefinitionVUI (Voice User Interface) is a way of operating through an exchange in which the user speaks with their voice and the device answers with sound.
ExplanationThe device converts spoken words into text or commands with speech recognition (音声認識) and reads its replies aloud with speech synthesis (音声合成). Because it works without looking at or touching a screen, it helps when your hands are busy or the screen is hard to see.
AnalogyIt is like asking a family member out loud to "set the timer for 3 minutes" while your hands are busy cooking, and hearing "done" in reply.
Memory hookThe V stands for Voice. Swap the G (Graphical) in GUI, where you work with on-screen parts, for a V, and you get a point of contact that uses voice instead of a screen.