Information mining from speech signal as the ultimate goal of data mining is concerned with science, technology, and engineering of discovering patterns and extracting potentially useful or interesting information automatically or semi-automatically from speech data. With the advent of inexpensive storage space and faster processing over the past decade, data mining research has start to penetrate new grounds in areas of speech and audio processing. A typical speech can be broadly defined as speech with emotional content, speech affected by alcohol and drugs, speech from speakers with disabilities, and various kind of pathological speech. Individual speech can vary because of different timing and amplitude of the movement of speech articulation. Physical mechanism of speech undergoes changes, which can affect the nasal cavity resonance and mode of vibrations of the vocal cords. A series of environmental variables like background noise, reverberation and recording condition have also to be taken into account. In essence every speech production is unique and this uniqueness makes the automatic speech processing quite difficult.