To an outsider this may sound like gibberish, but to the musician it is the key to the soul of the music. Any syllable used has to represent the beat. Just like improvising on an instrument the vocalist's solo comes from the heart. Lee B. Brown's theory on jazz contrasts Andre Hodeir's theory about what jazz is. One point that Hodeir makes is that there is hot jazz and swing.
Swing produces a sort of relaxation feel and hot playing creates a tension.
Hodeir's theory proves that jazz is full of emotion. The hot jazz gives the feel of tension. It has the short beats and rests which make people want to jam to, but swing can also give a feeling of tension to its listeners. It is the value of the music, not the style. The band can swing so hard that the soloist will just ride on top of the beat which will make the crowd crazy, but it can also sound so sweet that the crowd sits back in their chairs and relaxes to the slow swing.