On March 8, the following question was posed on EWTN’s Canon Law Forum:

In our diocese, a number of parishes have begun to employ the “dialogue homily” during Mass. In this format, the priest begins the homily, and the lay preacher then delivers a speech (that frequently references the Gospel reading) after the priest has finished and returns to the presider chair. Following this, the Creed is recited. This policy is furthermore permitted by our diocese. (more)

The following answer was provided by the Reverend Mark Gantley, JCL:

I do not know of any provision that permits dialogue in homilies, outside of Masses for children as you mention. The purpose of doing it for children is to engage their attention to the message, not so that some insight into the faith might be offered by children.