Speech perception
Agnosia is "the loss or diminution of the ability to recognize familiar objects or stimuli usually as a result of brain damage". There are several different kinds of agnosia that affect every one of our senses, but the two most common related to speech are speech agnosia and phonagnosia.
Mirrored-self misidentification
Viewing one's own facial reflection in the mirror causes neurological changes in the right inferior frontal gyrus, the right inferior occipital gyrus, the right inferior parietal lobe, and the right parietal area. These changes, which all occur in the right hemisphere, highlight the role of the right hemisphere in self-related cognition and processing and support the theory that the right hemisphere is the most likely substrate for the "self" in the brain. When the right hemisphere is damaged in any way, the patient will most likely lose the ability to recognize one's face - the most common feature of self-recognition. When paired with mirror agnosia or impaired facial processing, damage in any of these areas of the right hemisphere of the brain can lead to difficulties in self-recognition. Delusions such as mirrored-self misidentification can then develop.