Excuse my ignorance. I'm writing a work of fiction wherein an archeologist finds a tomb that contains not only the bodies of an unknown/unstudied society, but also samples of writing in that society's language. My question is how would that language and the text samples begin to be deciphered. if you could include answers that deal with both the theory and the application of doing so. I have been researching this on my own for some time but in my research I keep hitting a wall when it comes to certain things, and generally I've been going down rabbit holes each time I think I might be close to answering my question. (A definition of a study or a theory leads me to another definition, and another, and another.)
The first thing I learned was the near impossibility of decoding a language when one has no related source (i.e. the Rosetta stone for hieroglyphics) so would it be easier if say the original writer of the ancient text first began writing in Latin or some other well known language before re-writing the text in their own language? This is where the "theory" comes in. The idea is that the ancient writer is the first and only person to ever write down this language, so it would be basically be the origin and sole source of that written language. Would it be easier if they used the Greek alphabet or had part of the sample written in another known language like with the Rosetta stone? I've loved this website and many of the questions/answers are very helpful, but nothing quite gives me all the answers I'm searching for when it comes to theory and application .
Thank you for any help or direction!