The United States Conference of Catholic Bishops offers this precious recording of the moment (at 7 minute 40 seconds in) when Pope Francis went off-script and spoke from his heart about the good news and its connection with the family.
Visit their site to see on-demand all the videos of the Pope’s appearance.
Zenit offers a transcription of his comments… http://www.zenit.org/en/articles/pope-s-off-the-cuff-address-to-families