Yes.
I understand this thread is about Deaf and Mute.
But my daughters reading a magazine about hearing lady chose not to talk to strangers all her life only to her immediately family at home.
She went ahead and married to a family friend's son, and he accept for who is she, and she become pregnant, he took her to see Gyn/Obs Dr and he asked lots of questions about her unborn baby, this woman won't speak a word, and her husband speak for her, this doctor is not happy saying "How do you know she is ok"? - good question!!
My daughters find it interesting to know very rare hearing people chose to be Selective Mutism as a choice after something anxiety disorder that scared them for life mostly started at school.
This Mutism woman saying (via her husband's) she is anti-social, wish to join other Mothers at school groups for a cuppa chatting, but don't have the courage to mix with them!!