When my nephew was nine or ten he announced that he wanted to be a rabbi. “What does a rabbi do?” I asked him. “Announce pages,” he said.
The interaction between the rabbi and the cantorial leader – whether the latter is a professional or a lay person – can stir interest and excitement. There is the variation and color that two voices provide. And there can be the element of surprise: which voice will I hear next? The latter is even more the case when the Hebrew and English parts are passed back and forth between the two leaders. To do this, leaders might meet in advance, decide on the pace of the service they are to conduct, the overall architecture of the service, and the ways in which their interaction will help make the service moving and effective.
There are many ways this can be accomplished. Our colleague, Rabbi Jan Uhrbach, has experimented with someone reading the English translation while she hums a nigun softly. At times there is a pause in the reading and the nigun is sung more loudly signaling to the congregation that they should join in. In this way, the English takes on the quality of Hebrew davening.
To hear discussion of different techniques for leading High Holiday services in particular, visit Derekh.org, where you can listen to a podcast by myself and Rabbi Jan Uhrbach.