soft voice; gentle voice; kind voice
Describes a voice that is gentle, kind, or tender in tone. Often used to convey warmth or comfort.
彼女はいつも優しい声で話す。
She always speaks in a soft voice.
優しい声に励まされて、また頑張ろうと思った。
Encouraged by the gentle voice, I felt like trying again.
A straightforward compound of 優しい (gentle, kind) and 声 (voice). No special historical derivation.