Contents Introducti

The actuality of the theme may be defined by the fact that the phonetic system, or structure of English, like that of any language, is a systemic combination of all the 4 components of the sound matter of language and the first and basic component of the phonetic structure of English in the system of its segmental phonemes which are divided into vowels and consonants. The modifications of vowels have not been thoroughly well investigated in English and it is one of the reasons for the choice of the theme.
The aims and the tasks of the work may be formulated in the following way: a) To find out the nature of modifications of speech sounds.
b) The influence of neighbouring sounds on each other and their character. c) Changes that occur with vowels.
d) To establish modification properties of English vowels in connected speech. e) Modifications of vowels in connected speech.
Object of the research: English vowels, vowel changes and modifications, the phenomenon of reduction, reduced words, and elision in English are the main objects of my research.
Methods of the research: the main method in my research is the method of phonological analysis of vowels and their changes in connected speech

Investigations have been carried out on a vast language material, based on the literary type of English pronunciation, upon the investigations made by a number of well-known English, Russian and Uzbek linguists as V. A. Vassilyev, A.A. Abduazizov and some others.

The theoretical value of the present paper is that its results may be used in delivering lectures in the theoretical phonetics of modern English.
The practical value of the research is in the fact that its results can serve as the materials in practical lessons of phonetics and at seminars in the theoretical course of English phonetics and can be used:
1. in teaching English phonetics to Uzbek and Russian students. 2. at the lessons of seminars of English phonetics.
3. in delivering lectures in theoretical phonetics.

The expected results of the research work may be formulated in the following way:
a) The nature of modifications of speech sounds and the phenomenon of assimilation will be defined;
b) The change of neighbouring sounds and their influence on each other will be analysed;
c) The most important features of phonetic phenomena that happen with vowels in connected speech will be explained;
d) Characteristic features of assimilation will be described.