How is the recitation in supererogatory (Sunnah) prayers performed?

Recitation in supererogatory prayers is like recitation in obligatory prayers: one begins with Fatihat al-Kitab (the opening chapter of the Qur’an) and then recites what is easy from the Qur’an. It is legislated to prolong the recitation in supererogatory prayers, except for the two rak'ahs of Fajr, in which it is recommended to shorten the recitation, due to the hadith agreed upon by Bukhari and Muslim narrated by Aisha: "The Messenger of Allah, peace and blessings be upon him, used to pray the two rak'ahs before Fajr, and he would make them so light that I would say: 'Did he recite Umm al-Kitab in them?'" Recitation in supererogatory night prayers is audible, and in supererogatory day prayers, it is silent, unless it is a congregational prayer, like the Eid prayers.