ABSTRACT: Immense advancement in technology has enabled an easy speech & speaker recognition and signal processing. This review discusses the formation of speech, various mechanism and techniques used in identifying, extracting and deciphering the speech signals and its processing. The rapid pace of the field demands active efforts to ensure that this breakthrough technology is used responsibly for effective signal recognition and processing. This technology has a major importance in Forensics as it assists in investigation process, by this they can repair, enhance, and analyse audio recordings using a variety of scientific tools and techniques.