Theory of phonetics

A speech sound is an element of a speech sequence which is formed with the help of our speech apparatus. Speech sounds can be distinguished within a sequence. A sound becomes a speech sound if it has a certain set of basic characteristic features that make the sounds identifiable and recognizable in a speech flow, despite various changes a sound can undergo under the influence of its neighbours. Environment influences it and it is included in its definition (tone, emotions...). Sound taken isolated is not a system. We have to know its system, environment, and context. We would hardly be able to consider it because we would know next to nothing about is interrelations with its neighbours.
For example, Georgian “R” - is front in its system (a nephew can’t be without an uncle or an aunt).
A sound can be perceived only when any element features are being seen against the background of the neighbouring features. We can roughly define the system as the same total or set of units or elements where quality of each element is defined and shaped by the qualities and characteristics of the other units and elements. Unlike any other sounds speech sounds, if not taken separately, can form meaningful combinations like morphemes, roots, words, endings...
For example, to whistle (surprise, danger). Tone depends upon a situation.
Let’s compare such notions as phoneme, segment and a speech sounds. They all contribute to the producing sounds.
When we talk about the sounds of a language, the term “sound” can be interpreted in two different ways. In the first place, we can say
For example, that [t] and [d] are two different sounds in English, [t] being fortis and [d] being lenis and we can show how they contrast in different pairs: tie-die, seat-seed, etc.
For example, table – an ideal image. t has all its characteristics: forelingual, apical-
alveolar, occlusive, plosive, devoiced.
little – it’s an allophone of t. Lateral plosion.
At that – t becomes dental.
In the second example the sounds differ in one articulatory feature only. To avoid ambiguity, the linguists use two separate terms: “phoneme” is used to mean “sound” in its contrastive sense, and “allophone” is used for sounds which are variants of a phoneme: they usually occur in different positions in the word.
Phoneme – is an idea. It has some characteristics which manifest themselves in a context. The definitions of the phoneme vary greatly. The materialistic view of it was originated by the Soviet linguist L.V.Shcherba. According to his view the phoneme may be viewed as a functional, material and abstract unit. V.A. Vassilyev looks upon the phoneme as “… a dialectal unity of these aspects because they determine one another and are thus interdependent” (Vassilyev V.A. English Phonetics: A Theoretical course. – M., 1970, p.141). He defines the phoneme like this: “The segmental phoneme is the smallest (further indivisible into smaller consecutive segments) language unit (sound type) that exists in the speech of all the members of a given language community as such speech sounds which are capable of distinguishing one word of the same language or one grammatical form of the same word.(#, p.136). This definition is to long and complicated for practical use. The concise form of it could be: “The phoneme is a minimal abstract linguistic unit realized in speech in the form of speech sounds opposable to other phonemes of the same language to distinguish the meaning of morphemes and words.”