Particularly in jazz songs, people sing syllables slightly before or after the chord changes--another problem is that, except for when there is a chord change, Walter's technique does not make it clear where the beats of the measure fall, so you can't really tell, without experimenting, whether it there is one count between chord changes, or there is are four, or even eight--

I will never understand why you folks are so completely resistant to the chord charting system that Jazz players have used for years, which simply is to use slash marks, showing two chords per measure(first and third count)whether there is a change or not, so you can simply look at the chart and play, whether you know the tune or not--

|CE7/A7A7/FA7/DmDm/
FB7/CA7/D7D7/DmG7

If you know the melody, you can sing it or play it over the chords, and if you don't, nothing will help you, outside of the music, anyway--