As verbs the difference between shrieked and whisper
is that
shrieked is (
shriek) while
whisper is to speak softly, or under the breath, so as to be heard only by one near at hand; to utter words without sonant breath; to talk without that vibration in the larynx which gives sonorous, or vocal, sound.
As a noun whisper is
the act of speaking in a quiet voice, especially, without vibration of the vocal cords.