There are several ways that deaf people tell others that they are deaf. Deaf people are not all alike Some deaf people will use their voices, others will not. Some deaf people who use their voices may be highly intelligible, others may be difficult to understand. Some deaf people speechread, others do not. Some deaf people fingerspell, others do not.
Some deaf people sign, while others speak in all communication situations.
Some deaf people use Native Sign Language, while others sign in English word order or use a manual code for English. Some deaf people wear hearing aids while others do not. Ask the deaf friend. Deaf people depend largely on their eyes to receive information. Whether communication is spoken or signed, clear sight lines and proper lighting are a must.