Rick: "According to my current understanding the PT's were supposedly a collection of texts that had been assembled over a period of centuries, rewritten, reedited, recollated and finally carved onto the pyramid of Unas."
Some comments on the PTs by J.P. Allen, one of the foremost translators of ancient Egyptian texts:
"Although they are first attested in the pyramid of Unis, most of the Pyramid Texts are undoubtedly older. With few exceptions, their grammar is that of a stage of the language that disappeared from secular inscriptions at least fifty years earlier, and the architecture of the pyramid chambers that they reflect came into use at the end of the Fourth Dynasty, more than a hundred years before Unis's time. Some of the texts reflect burial practices that are even older, in earthen graves beneath tombs built of mudbrick. Newer spells that first appear in the later pyramids, however, incorporate features of the contemporary language.
Overall, the Pyramid Texts give the impression of a corpus that had been in use for some time before it was inscribed in Unis's pyramid and one that was continually revised and amplified during the reigns of his successors.............Although the Pyramid Texts of the Old Kingdom were inscribed only in royal tombs, the texts themselves give evidence of a less exclusive use. Many of them were originally in the first person, meant to be spoken by the deceased's spirit and thus not restricted to a particular individual. Those addressed to the deceased by name occasionally preserve indications of a generic original, with directions to the celebrant indicating where the deceased's name was to be inserted. A few spells from the king's pyramids also seem to make reference to the deceased as someone other than the king himself.
Occasional mistakes in the use of some hieroglyphic signs indicate that the master from which the texts were transcribed to the pyramid walls was a papyrus scroll written in a semi-cursive script - in line with the comments of the preceding paragraph, probably a manuscript that was not specific to any one individual. The inscriptions in the pyramids of Unis and Pepi I, which have been studied in detail, show traces of editorial revision after the texts were first carved - in the case of Pepi I, even amounting to revision of entire sections of a wall. Most of the editorial revisions have to do with the replacement of an original first-person pronoun by the deceased's name or a third-person referent, thus "personalizing" the texts for each pyramid....
CT