If I was approaching something from a language-first style, I'd probably try to figure out what kind of cultural and geographic features would influence the language in it's current form. Just some mind vomit without giving hardly any thought to it:
- language slow and sing songy could indicate a more leisure focused society, and that would mean either nearby natural resources, or a robust engineering that handles base needs
- Or it could be a culture that tries to embrace peace and uses song and dance to put guests at ease
- guttural or short language could be a battlng society, where info needs to be communicated efficiently
- Or it could be a culture that uses spoken language as only part of their method of communication.
Just spitballing here. Hope there's a nugget of something in there.