We consider the current issue of the relationship between different levels of language system on the basis of the relationship between phonology and syntax. These areas occupied a central place in V.G. Rudelev’s studies. We analyze Professor V.G. Rudelev’s doctrine about the sentence from the standpoint of his phonological views. The object of the study is the syntactic doctrine of V.G. Rudelev, represented by his reasoning about the sentence. The methodology of the material study is based on the oppositional method, which allows us to see the possibilities of its application to explain the universal nature of the information-theoretic approach to the study of different areas of linguistic knowledge. Neutralization in its phonological understanding is used as a linguistic mechanism in describing the relationship between different types of sentences. The use of phonological mechanism of neutralization allows V.G. Rudelev to identify the relationship between simple and complex sentences. In the system of complex sentences, he comes to the conclusion that hypotaxis is marked in relation to parataxis. In the system of simple sentences, the main attention is paid to the analysis of verbal and interjectional sentences. The oppositional method allowed V.G. Rudelev to come to the conclusion about the marking of syllabic sentences and, based on neutralization, about their higher linguistic rank, “weight” in human speech activity. We express our attitude to the consideration of the doctrine of sentence in the aspect of phonology. The considered V.G. Rudelev's doctrine about the sentence in the aspect of his phonological views allows us to see and comprehend the relationships in syntax in a dynamic way. This is most clearly demonstrated by the use of the phonological concept of neutralization in syntax. However, it is necessary to take into account the specifics of syntax as an area of bilateral syntactic units.