It's a trick! Don't type the words of the Scroll of Life into your keyboard! It's a trick! The mummy (titular) will get you! Whatever you do, don't type those words!
The recitation of the prayer is shown in two scenes. In one the first half is said in Egyptian with the latter half in English, and in the second scene we get to hear the first half in English (before the mummy steps out of his sarcophagus, scaring the elder Banning out of his mind), but it isn't completed.
Putting the two together, basically we have this:
"Restore to life oh thou Lord of Souls, oh thou Lord of the Tomb, the Mighty One of Amentet. Let not these limbs be without movement, let them not pass away, and let them not suffer from corruption. Eternal Ka the double, oh Ba the soul, thou strong Ab the heart, make supple these limbs and strong these sinews, refill oh my soul this heart with tenderness, that he may walk again the land of Kem in all Thy Strength and Beauty, and wear once more the Uadjet."
Now just a min who would they have gotten for the job if Chris's guy hadn't mucked up? I don't think they would have had many volunteers.
One other item: Now that the big guy's work was done what did Mehemet Bey have planned for him? It just a bit funny how not be able to talk Kharis was unable to tell him he didn't kill John Banning on the second try.