Instead of reporting some news, I want to ask a question and I urge all readers with knowledge of signing to contribute.
One of the differences between speech and writing is tone of voice, which enables speakers to underscore a point, or to speak sarcastically, or to contradict themselves (e.g., shout angrily, "I'm not mad.") Emotional vocalization can also stand alone, allowing for moans, sighs, etc.
My question (springing from a vast pool of personal ignorance): To what extent are these emotional vocalizations duplicated in signing? Do signers ever feel the need to express the equivalent of, "Don't speak to me in that tone of voice, young man?" How does one go about being sarcastic while signing? Moans and sighs seem pretty automatic, but is there any sort of equivalent in sighing? Is the signing equivalent of tone-of-voice an inevitable part of signing (as it seems to be in speech), or is it something deliberately added.
Answers from experience as well as references to any literature on the subject will be greatly appreciated.