CAN DEAF PEOPLE HEAR?
It is surprising to many people outside of the Deaf Community, but Deaf people can often hear. The Deaf are considered deaf once they have passed a certain decibel (dB) hearing loss. Many people who are profoundly deaf can still hear planes, dogs barking, etc. Hearing a sound does not mean that Deaf people can understand speech. A person with a significant hearing loss generally has difficulty or inability to hear speech even when aided.

IS SIGN LANGUAGE USED BY ALL DEAF PEOPLE?
No. Many Deaf people choose to communicate through speech, lipreading, or Cued Speech. Sign Language is of course not universal. Each country, and many regions within the U.S.  have Signs that are unique. Communication across cultures is often very difficult and Signed communication within a culture has it's opportunities for miscommunication.  

WHY DO THE DEAF NOT CALL THEMSELVES HEARING IMPAIRED?
Some people with a hearing impairment do use that term. Those individuals are usually latened deaf, or not Culturally Deaf. Members of the Deaf Culture do not consider themselves "impaired" hence most people within the Deaf Community and the Deaf Culture do not prefer the term "impaired" but rather "Deaf."  The term "Deaf" is a validation of who they are.