Put a Slinky in your hands and play with it for a moment. Now, think of the left hand as the "set up" of the line. If you don't have that end in your hand, the Slinky doesn't work very well, does it? If you don't set your line up, deliberately singing THAT LYRIC on THAT PITCH, your line is sabotaged.
Think of the right hand as the "follow through". Drop that end of the Slinky. Slinky doesn't work anymore. If you don't communicate and support the end of the line, the audience is left to wonder what you said (drives them crazy and not in a good way). And... your high note in the middle of the phrase is sabatoged.
When you sing or speak, set your lines up and completely follow through. And play with Slinkys a lot. And ask my students about hoola hoops and Martian Popping Things:)