What is the term for the fluctuation in voice that reflects the speaker's mood?

The term that refers to the fluctuation in voice reflecting the speaker's mood is intonation. Intonation encompasses the rise and fall of the voice during speech, which is influenced by emotional context and can convey nuances of meaning. For example, a higher pitch may suggest excitement, while a lower pitch could indicate seriousness or sadness. This vocal variation is crucial in effective communication, as it helps listeners interpret the speaker's feelings and intent beyond the literal words used.

While volume relates to how loud or soft a voice is and pitch pertains to the highness or lowness of a sound, neither of these specifically captures the emotional aspect of voice modulation. Inflection, on the other hand, refers specifically to the changes in pitch or tone to emphasize certain words and is a component of intonation but does not encompass the broader emotional range that intonation captures.