Theory of phonetics

Theory II. Sonority theory by O. Jespersen. According to O. Jespersen each sound is characterized by a certain degree of sonority which is understood as acoustic property of a sound that determines its perceptibility. It starts with the open vowels as the most sonorous, continues through the close vowels, the sonorants, the voiced fricatives, the voiced plosives, the voiceless fricatives and ends with the voiceless
plosives as the least sonorous. For example,
.
P l a: n t
According to V. A. Vassilyev, the most serious drawback of this theory is that it fails to explain the actual mechanism of syllable formation and syllable division (*Vassilyev V. A. English Phonetics: A Theoretical Course. – M., 1970) According to the degree of sonority all sounds can be subdivided into the following categories:

Vowels и voice 100 % The word ритм has

S onorants р. м 2 syllables.

(voice + noise)
Voiced
consonants
Voiceless т
consonants voice 0 %
A syllable here is seen as a wave of sonority. The scheme also allows us to define the borderline between syllables as a place of minimal sonority. There is some other example:
V owels а о а voice 100 % The word аорта has

Sonorants . р 1 syllable.

(voice + noise)
Voiced
consonants
Voiceless т
consonants voice 0 %
This theory is convenient, still it is not applicable in those cases when we have 2 adjacent vowels.
Theory III. Due to the analysis of articulatory or motor aspect of the syllable we could start with the so-called expiratory, or chest pulse or pressure theory which as based by R. H. Stetson (*Stetson R. H. Motor Phonetics. – Amsterdam, 1951). This theory is based on the assumption that expiration in speech is a pulsating process and each syllable should correspond to a single expiration so that the number of the syllables in an utterance is determined by the number of expirations made in the production of the utterance. The major accent in this theory is placed upon the force of articulation. We talk more about breathing out not of breathing in. A pulse is a result of contractions of muscles. Thus the idea is that we speak portion by portion. In obvious cases indeed the number of pulses coincides with the number of syllables. But the fact that in a phrase a number of words and consequently syllables can be pronounced with a single expiration makes the validity of this theory doubtful (* Торсуев Г. П. Вопросы акцентологии современного английского языка. – М.-Л., 1960). For example, сорокапятитысячный. In spontaneous pronunciation of this word in Russian it is hard not only to count the number of pulses, but it is next to impossible to count the number of syllables. The way we do it is subconsciously. Another example: “literary”. We can probably say there are 4 syllables in this word. However we can’t be categorical about it because in a natural conversation in words of this type reduction is very active and what we actually say it does not always coincide with the dictionary or transcription image. The 2 sounds “r” in “literary” are likely to merge into one long sound “r”. This also affects the number of syllables. It also seems to be reduced. To sum up this theory has at least 2 weak points:

1. 
   The number of pulses obviously depends on the style of pronunciation.
   
2. 
   It is connected with the first point. It is dependent on the tempo or pronunciation.
   

They are interconnected because we can’t change over from one style to another without suprasegmental factors causing significant changes. To clarify the point, you can’t go from so-called full literary style down to colloquial speech without changing the tempo, melody, pausation, etc. One complements the other.
For example, Выходите? It is in formal style.
Выходьте? In colloquial speech we even drop sounds.
Выхоите? We are careless about it.
The same can be said about these examples: “смотрите” and “сотри”, “здравствуйте” “здрасти”.