How deaf is 'deaf'?

When interacting with deaf people, you notice that most deaf people can understand unsigned speech as they still have some hearing, or can lip-read with ease. Some hearing impaired will have grown up in a hearing family or gone to a hearing school, and most will have friends who cannot sign.Because of this, signing is often not essential for communicating with the deaf, although there is no question that it makes everything a lot clearer. 

You may be wondering, how much can deaf people hear?
Very few deaf people are completely unable to hear anything.

                       These are the basic different levels of hearing impairment:
-Mild deafness:  People who suffer from this find it hard to distinguish words/ sounds in noisy places. This can be corrected using hearing aids, but in mild cases this might not be necessary. People suffering from Mild deafness may not need sign language, and may not define themselves as being part of deaf culture.
-Moderate deafness: People who suffer from moderate deafness are more likely to need hearing aids, but again they may not need to use sign language as they can still hear people- although the words are often blurred. 
As they can hear some words, they would be more likely to use Sign supported English (S.S.E) or Signed English (S.E) as BSL has a completely different grammatical set out to the English language.
-Severe deafness: This is when people are more likely to start relying on lip read or sign language. If a person if born deaf they are much more likely to use sign language rather than if they develop it in their later years.
-Profound deafness: The quietest sound they can hear is about 95 decibels. Suffers of profound deafness may rely on lip reading or sign language depending on when their deafness developed. 

For more information on the different types of hearing impairments, see : http://deafsign.com/ds/index.cfm?scn=article&articleID=30