The sharing of a language (American Sign Language) bridges racial, gender, class, and ethnic differences among the American Deaf community. As previously stated, not all deaf people will use ASL or other signed languages. It is always appropriate to ask the deaf person how s/he wishes to communicate.
Speechreading, historically known as lipreading, is is an inborn talent, and one with which many Deaf people are not born. It is possible for an expert lipreader with high English proficiency to combine what is visible on the lips with environmental cues, knowledge of subject matter, body language, and facial expressions to understand a percentage (50-75%) of what is said. However, less than 5% of profoundly deaf people are able to read lips at this level.
ASL shares no grammatical similarities to English and should not be considered in any way to be a broken, mimed, or gestural form of English. In terms of syntax, for example, ASL has a topic-comment syntax, while English uses Subject-Object-Verb. In fact, in terms of syntax, ASL shares more with spoken Japanese than it does with English. - Deaf Library Online
Because ASL is a visual language, there is a different set of rules for interactions or etiquette around communication than there is for English. For example, eye contact is extremely important in ASL. In a signed conversation the people involved in the conversation must always look at each other. For Deaf people, then, breaking eye contact or no eye contact during a conversation shows indifference. - The Vera Institute of Justice, Accessing Safety Initiative: Understanding Deaf Culture
Hearing can be done almost passively, but lipreading takes sustained, concentrated effort. - Lipreading as an Imperfect Skill