In many software engineers' view, much of their lives consist of writing documents. From the perspective of this course, we would prefer to say that their lives consist of performing work to gain understanding, which will be delivered to their colleagues according to the protocol specified in their process. Hence we are aware that the work is always understanding, and the process tells what understanding we need to convey to them. It, therefore, indicates the suitable language for each document. These considerations can inform a description of the actual job to be done with each of the documents; User Requirement, Software Requirement, Architectural Design, Detailed Design, and Test Specification, that an engineer produces.
There are two more general points that should be made. Firstly, the job does not consist of producing reams of unintelligible gobbledegook that no-one will ever read, that looks like `engineering documents'. The first person to quote a reference, full of slashes and decimal points, in the main text when it should have been in an appendix if anywhere, wasn't just being rude to his or her readers, they were setting a trend that has devalued the whole of our art. Use simple, normal language (including specialist terminology where necessary, but not made up for the sake of it), to tell the reader what they need to know.
The second point regards the format. In any stage of the software engineering process, people use understanding to find and propose pattern. If they knew what they were going to find, they wouldn't have the job, because somebody would be setting up a COTS product instead. So we don't necessarily know what the worker will need to present, so how can we tell them how to present it? Standard formats in processes should not be taken as exclusive. All decent ISO 9001 processes have provisions to tailor the required sections of a document where appropriate. Make proper use of these, and if the structure of the document emerges during the writing, you can still put an insertion in the Project Management Plan to describe your chosen format. This is what ISO 9001 is all about.