Spoken language is the most natural way used by human to communicate information. Speech signal conveys linguistic information as well as speaker information (e.g. emotional, regional and physiological characteristics). Such human ability has inspired many researches to understand production for developing the system that automatically process the richness of information in speech, this speech technology has many applications to find out \"Who is speaking\" means speaker recognition system. This paper gives an overview of major techniques developed in each stage of speaker recognition.