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.
Amusia
Other than their inability to hear music, which is most likely due to a genetic defect, the rest of an amusic's brain remains normal. The only effect is on the ability to tell different notes apart due to the separation of two key areas in the brain. Most sufferers of amusia describe music as unpleasant. Others simply refer to it as noise and find it annoying. This can have social implications because amusics often try to avoid music, which in many social situations is not an option. In China and other countries in which identical words have different meanings based on pitch, amusia may have a much more pronounced social and emotional impact: difficulty in speaking and understanding the language.