Cats And Dogs Whispering

Whispering (Latin: vox parva) is an unvoiced mode of phonation in which the vocal cords do not vibrate normally but are instead adducted sufficiently to create audible turbulence (a 'hissing' quality) as the speaker exhales (or occasionally inhales) during speech. This is a somewhat greater adduction than that found in breathy voice. Articulation remains the same as in normal speech.
In normal speech, the vocal cords alternate between states of voice and voicelessness. In whispering, only the voicing changes, so that the vocal cords alternate between whisper and voicelessness (though the acoustic difference between the two states is minimal).
There is no symbol in the IPA for whispered phonation, since it is not used phonemically in any language. However, a sub-dot under phonemically voiced segments is sometimes seen in the literature, as (ʃʊ̣ḍ) for whispered should.