In every phrase of vocal music, there is usually one word that occupies a special place. For me, the operative word of a phrase creates a kind of musical gravity so that the other words in the line flow towards and away from this point. The operative word is the key word of a phrase of text which both imparts meaning and implies direction for the phrase.
Example: In the well-known phrase “I come to the garden alone while the dew is still on the roses” the operative word is ‘alone’. It embodies the central idea of the song; personal communion with God. So if it is sung with empathy and understanding the whole phrase will be infused with the right heart. And it so happens (as in all good marriages of lyric and melodic line) that the word ‘alone’ occurs at a critical musical point in the phrase as well. After all, the line rises to that point and requires direction as the singers approach the word ‘alone’. So the lyric and the melody both demand an empathic rendering of the word.
If the singers have been led to discover the operative word and work together to create this sense of gravity, then the whole phrase will make more sense both musically and textually. To get them on board I would simply ask, “What is the operative word in this phrase?” I find that having the operative word in mind helps the singers create musically sculpted phrases that have clearer meaning for the listener.