A character voice is a specific way of talking to indicate you are speaking in-character. It can include diction, the use of a funny accent, body language, and alterations in the sound of your voice. A character voice can be helpful for establishing a separate personality for your character, aiding in immersion, separating in-character conversation from table chatter, and entertaining others.
Some people feel embarassed or awkward when using a character voice.
It is important when selecting a character voice to invent something distinctive and fun. Be wary of offending others with thoughtless stereotypes and caricature.