The fundamental mode of communication among humans is speech and in the case of

machine-human interface; verbal language has been believed as the natural method. When

communication with machines is carried out, it is very difficult and slow-moving in

magnitude when realized via keyboards, mouses and other devices. Thus, speech feed-in is an

important constituent to making this communication easily accessible. Also, humans see speech as a

great source of information. Therefore, persons who are not literate or have vague about computers

can easily access computers by employing speech instructions. Even people with some physical

disability who are not able to type or click with their hands can use their speech to operate the

computer. Even people who are proficient in operating computers can speed up data entry, sending

emails and other documents using the speech input methods. Furthermore, this mode of

operation possesses many advantages. For example, while driving, the hands of the driver are

busy steering the driving wheel and he cannot type on his mobile. In such a case speech

is a good input option. GPS (Global Positioning System) is an example of a speech-based

system being used. Another example is speech-enabled dialing, where the user can just ask the

device to call a particular person, without dialing his number.

The common and efficient means of communication among humans is through 'speech'. To process speech

means to extract useful information from it, processing includes the implementation of electric

signals on the acoustic pressure waves collected from human vocalization and applying

mathematical analysis to it. The field of processing speech involves the natural operation

of analysing speech, coding, augmentation, synthesis, and recognition. Analysis of speech is

the study of its creation mechanism to make a mathematical model of physical phenomena.

Speech coding aims to keep information about specific speech parameters for later retrieval. The

method of refining precision and quality of speech which is noisy utilises various algorithms is

recognized as speech enhancement [2]. Producing artificial human speech using coded information is

known as the synthesis of speech. The method of inverse synthesis is the capability of a program or

machine to classify the linguistic contents mixed up in the speech signal.