Recently in the bus I sat next to two persons conversing* in sign language. In their conversation, they were not only using gestures and mimics for expressing what they wanted to say but also were constantly making whispering sounds all the time when doing this.
What are these sounds for? I thought deaf people actually cannot hear anything, how can sounds support the conversation? If these sounds hold semantic information, is then anything missing when you see sign language expressions in which these sounds are not even sensible for non-deaf people? I think of news shows of certain public broadcasting stations which often include translations* in sign language, there no whispering sounds are noticeable from the translator.
*I hope 'converse' is the right verb for an exchange between two people in sign language and I hope 'translate' was the right word to use in this context. Please forgive me if that was insensitive however I am not familiar with the details of sign language yet.