[cdcarter]

Do you have any written posts or documents about this language and your design decisions?

[whereistimbo]

https://elv.sh/

[xiaq]

I gave a talk about the design: https://www.youtube.com/watch?v=wrl9foNXdgM

As the sibling comment mentioned, you can find documentation on Elvish itself on the website https://elv.sh. There are tutorials and (not 100% but fairly complete) reference documents.