Tell Him -- Lauryn Hill

I've always thought Lauryn Hill has had one of the most beautiful voices I've ever heard. Today "Tell Him" came up on my shuffle and I decided to listen closely to her technique to find out what the beauty was made of.
The first thing I noticed was quite remarkable and kept me busy for a while.
When she gets to the line ,
"I'll envieth not" she begins a motif that she continues for the whole song.
Its like a 2 note run. On each note that she holds, she bounces back and forth on 2 notes continuously (as opposed to running up and down a scale every time as many R&B singers would). Its like a stripped down run or an extremely slow forced vibrato. This allows for a smoothness of transition when she does go into a more complex run. She just flows right into it.
I tried to imimitate this vocal technique and found it requires both lots of control of the vocal chords and lots of control of the diaphragm. A steady stream of a lot of air is required. The throat must be open and relaxed and the tone very warm.
I practiced with the metronome. At different speeds I went back and forth on two notes for about 8 counts of 4. The faster speeds required more vocal chord control and the slower speeds required more diaphragm control. This was a great exercise.
After doing this for about 20 minutes I felt very warmed up and at ease. And I tried a few runs and found they came very naturally.
I decided to try this technique with the song I'm currently working on. I'm alternating between my natural vibrato with this intentional vibrato and really discovering interesting and soulful tricks.

Tell Him