The Reports contain text in two different "dialects'': quotations from Enūma Anu Enlil and other standard omen collections are in the Babylonian literary dialect of the 1st millennium B.C., the rest in the sender's own dialect, i.e. either Neo-Assyrian or Neo-Babylonian. The writing is, of course, either Assyrian or Babylonian throughout each text.
According to their subject matter, the Reports can be subdivided into several groups. By far the largest group is those on celestial observations. There are a small number of Reports on omens from abnormal births (Šumma izbu); from fortuitous events (Šumma ālu); and on auspicious days (hemerologics).
Hermann Hunger
Hermann Hunger, 'Contents and Structure of Reports', Astrological Reports to Assyrian Kings, SAA 8. Original publication: Helsinki, Helsinki University Press, 1992; online contents: SAAo/SAA08 Project, a sub-project of MOCCI, 2020 [http://oracc.org/saao/saa08/ReportsonOmens/ContentsandStructure/]