Speaking clearly. Improving voice and articulation: Фонетический практикум. Фомиченко Л.Г. - 72 стр.

72
J.D.           Like that, you see. The word «ought» is said on a
               slightly lower note, and the sentence continues
               on that lower note until it gets to the very last
               syllable.
Miss Tooley.   How do you think we ought to start? How do you
               think we ought to start?
J.D.           Again, you see. The word «start» is on a slightly
               lower note and not only that, it falls as you say it:
               «start — start».
Miss Tooley.   Yes, it does. It falls right down to the bottom
               of my voice, listen: «How do you think we ought
               to start? How do you think we ought to start?»
J.D.           So the sentence is really in three parts,
               corresponding to the number of stressed syllables:
               «how», followed by four weak syllables, then
               «ought», followed by one weak syllable; and, lastly,
               «start», followed by nothing at all.
Miss Tooley.   How do you think we — ought to — start?
J.D.           We can make a good rule out of that. In sentences
               like this, the first stressed syllable and any weak
               or unstressed syllables following it, are said on
               a fairly high note; the second stressed syllable and
               any more weak syllables after that, are said on
               a slightly lower note, and the same with the third,
               and the fourth, and so on until you come to the
               last stressed syllable of all, which not only begins
               on a lower note than the previous one, but also
               falls right down until it can scarcely be heard at all.
               Well, now we must go back to the beginning and
               see if our rule works for some of our other
               sentences.