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.
Neural processing for individual categories of objects
Studies of patients with brain damage have revealed pure agnosic disorders that selectively impair recognition of specific object categories. Such agnosic disorders have been reported for faces (prosopagnosia), living vs. nonliving stimuli, fruits, vegetables, tools, and musical instruments among others, suggesting that such categories may be processed independently within the brain.