A Little Lerner and Loewe with a Mozart Kicker!

I really enjoyed watching all three clips.  I completely agree that a lot of the difficulties with being clear diction as a singer is producing a full and rich tone without compromising the vowels or consonants.  It takes a lot of vocal control (the right kind of control) in order to produce a steady stream of sound, without much interruption from consonants, in addition to maintaining the proper placement of vowels.  What I noticed the most about Stephen's singing is that he produced most of his words with a round shape to his mouth, without compromising the placement of the voice.  This undoubtedly came from many years of practice and training.  However, even in the production of [i], or other highly placed vowels, he did not draw his lips back but maintained a round shape with his lips (something that I am currently working on with my teacher).  The effect is that the sound remained completely forward and clear to the listener.