People all over the world tell stories, and different languages have different ways to introduce those stories. And there are patterns in these methods!
A couple notes:
For why seven is a ~mystical number, this video has some interesting stuff in the end half: https://www.youtube.com/watch?v=vpRd52dXHlQ&ab_channel=It%27sOkayToBeSmart
Definition of folktale is... difficult. I've gone with what sounded best and seemed to fit best with the kinds of stories these phrases are used for. Like, you get "Once upon a time" for things like Goldilocks, but not really for stories about Merlin, cause that's closer tied to history/real locations. And some cultures just don't seem to see stories in this way, or don't have a set stock phrase, so they aren't here. But I didn't want to talk about this for too long :P
You might notice there are ads now - I'm figuring out what I want to do with monetization/how much it's worth it. Half of whatever I make from this video, for at least the next month, will go to https://www.sola-afghanistan.org, an Afghan school for girls. It's probably not gonna be much but it'll be something :P
Patreon: https://www.patreon.com/nakarispeardane
Sources:
https://blogs.scientificamerican.com/literally-psyched/the-power-of-once-upon-a-time-a-story-to-tame-the-wild-things/
https://www.theguardian.com/books/2019/apr/19/here-is-a-story-story-it-is-how-fairytales-are-told-in-other-tongues
https://www.theparisreview.org/blog/2018/05/23/once-upon-a-time-and-other-formulaic-folktale-flourishes/
http://www.chitrasoundar.com/story-starters/
https://forum.wordreference.com/threads/once-upon-a-time-beginning-of-a-fairy-tale.2225755/
https://www.reddit.com/r/AskEurope/comments/brderk/what_is_the_translation_of_and_they_lived_happily/
https://forum.duolingo.com/comment/30478921?comment_id=30478939
https://www.usaid.gov/somalia/news/next-generation-storytellers
https://qz.com/work/1298571/stories-literally-put-our-brain-waves-in-sync/
https://historyofyesterday.com/the-history-behind-once-upon-a-time-1d2eba810dcc
https://forum.wordreference.com/threads/they-lived-happily-ever-after-the-end-of-a-fairy-tale.2225730/
https://college.holycross.edu/projects/himalayan_cultures/2011_plans/ddemerau/scripts.html
+ replies and comments on these Twitter threads:
https://twitter.com/NomeDaBarbarian/status/1407554571786883078
https://twitter.com/csoundar/status/1114461222336913410
Village Ambiance by Alexander Nakarada
Link: https://filmmusic.io/song/6586-village-ambiance
License: https://filmmusic.io/standard-license
https://pixabay.com/photos/shell-fossil-old-ancient-stone-219665/
https://flickr.com/photos/gesika22/4089936494/
https://upload.wikimedia.org/wikipedia/commons/1/1b/FraMauroDetailedMap.jpg
http://expositions.bnf.fr/arthur/grand/ars_3142_256.htm
https://flickr.com/photos/hunky_punk/21014221984/