Chuchoter vs. souffler
The French words 'chuchoter' and 'souffler' both refer to a low level of speech, but convey different nuances in the way this is done.
Chuchoter
'Chuchoter' means 'to whisper' in the sense of speaking softly and quietly, typically intended for a discreet form of communication between individuals.
Elle m'a chuchoté un secret à l'oreille.
(She whispered a secret in my ear.)
Les enfants chuchotaient dans la bibliothèque pour ne pas déranger les autres lecteurs.
(The children were whispering in the library so as not to disturb the other readers.)
On entendait seulement chuchoter pendant la réunion confidentielle.
(Only whispering could be heard during the confidential meeting.)
Souffler
'Souffler' also means 'to whisper' but often implies prompting or cueing someone quietly, usually used when giving someone answers or hints without being noticed by others.
Il a soufflé la réponse à son ami pendant l'examen.
(He whispered the answer to his friend during the exam.)
L'acteur oubliait son texte, alors son collègue lui a soufflé ses répliques.
(The actor forgot his lines, so his colleague cued him with his lines.)
Peux-tu me souffler comment dire cela en français ?
(Can you whisper to me how to say that in French?)
Summary
'Chuchoter' is generally used for any soft speech or whisper and is associated with secrecy and discretion, while 'souffler' is more specific and often related to assisting someone by whispering information or answers discreetly. Thus, while both involve quiet communication, 'souffler' carries a connotation of guiding or helping through whispers.