Working on the spoken sentence, one must first learn the IC-1 volume contour characteristic of communication in the neutral style of speech, the role of the intonation center, the link in pronunciation [[ <--don't understand this]], and the lower volume in the post-stressed part of the phrase. This is followed by practice in identifying the position of the intonation center of sentences in connected speech, and understanding the use of other IC types in the narrative sentence.

Correct some spelling errors.
This is my guess as to what is meant, and it is still a bit awkward. Terms like "enunciative sentence" sound very odd. I could do better given the original Russian text.