help with backderiving a protolang?

[pachelbel]

I have one fairly well developed a priori conlang for my conworld, and a couple others in the same family for which I basically have a phonology, a grammar sketch and a few words. My goal is to figure out the protolang from which these would all have evolved, basically "what were the original colonists speaking when they landed on this planet".

I've looked for resources but only found ones for developing daughter conlangs from a protolang, not the other way around. Do y'all have any tips or resources for backderiving a protolang?
Thanks for reading ^^

[Salmoneus]

I would suggest identifyiing unusual features in the language and explaining how they would have developed. You can then cross-reference your answers with the related language sketches to make sure your proto-language could have lead to all the daughters.

[WeepingElf]

Working backwards this way is not easy. What you are essentially doing is what historical linguists call internal reconstruction; however, it is somewhat easier because your goal is not reconstructing the ancestor of your language but merely a possible ancestor that you can declare valid in your conworld. I had done just this with my Hesperic conlang family, for which I reconstructed a Pre-PIE to serve as the common ancestor of IE and Hesperic; however, I never finished that reconstruction and abandoned it when I found that Proto-Hesperic was to be a daughter rather than a sister of PIE, so I no longer needed to work backwards but could work forwards the usual way in diachronic conlanging.