I. Introduction
Today, the speech synthesis systems are represented by computer systems which can convert input text into output audio file – speech. The main task of these systems is primarily making life easier for example to people with physical disabilities, such as blind people, or to totally ordinary people and facilitating their day to day operations. The use of speech synthesis in practice is often faced with the reluctance of users to communicate with device, whereas synthetic speech acts artificially and creates a barrier in communication [1]. That is why the research in the field of speech synthesis is focused on the development of new advanced methods and their improvement in order to make final speech output from these systems as similar to the human interpretation as possible.