So... I have decided to make my own language families and am wondering how you make your own.
For me, I find that it helps to set out all of the modern languages that I want related in a particular tree and make connections from there based on how divergent I want them to be.
But enough about how I do it, how do you plan out your conlang families?
Synchronically. I've found that as projects get larger and larger, doing things retroactively gets more and more difficult. I have to start contorting languages and histories in ever-weirder ways in order to get it looking how I Wanted it to look.
Another thing that's happened as I've gotten into making full families is that I've started having to do a lot more worldbuilding. I need to keep a timeline of the languages so that I know when sound & grammar shifts happen in relation to each other. I need a working understanding of where the speaker groups are in relation to one another.
As dialects diverge I need isoglosses, which means I need a physical map. In offense against me, I like mapmaking, and I have detailed maps for my settings, but when it comes to mapping dialects and isogloss lines I've mostly ended up using quick blocky sketch diagrams in a notebook.
My projects take years IRL, and so my plans have often changed substantially as I've gotten into them, but for the Gavellian family I started with "I want these broad groups to exist" and cascaded groups down from a proto. I don't do that anymore. Again, lessons learned.
For my current project, I started with a single proto and have been developing strands of it in sync with one another. I have general goals for the divergent branches, but I'm working on them in generational chunks. Apply changes, create isoglosses, etc. I don't know when or how they'll lose intelligibility with one another.
I don't have a specific goal in mind for the entire project outside of "fun times with head marking" and my general aesthetic sensibilities.
tldr:
manage your timeline first, plan starting from proto down to youngest.
timeline logistics will be your largest headache.
either advance through the timeline simultaneously for every language in the family or keep meticulous notes on when everything relates to everything else
know where your speaker groups are physically in relation to one another


















