an incomplete list of my favorite headcanons
regulus + sirius are french and speak a couple languages each. both speak french and english—sometimes one other language (depending on the au). they grew up going between grimmauld place in london and the black manor in the french countryside.
evan + pandora are twins and also speak french and english. they were born in provins, france. they almost ended up at beauxbatons.
evan and regulus frequently end up having full conversations in french, much to barty's dismay.
barty speaks italian and english. his mother was from venice, and he was born there. he leans into the italian side of his family more because of how close he was with his mother.
james is mexican/latino and speaks spanish and english, along with a few french phrases (sirius knows some spanish insults).
remus is welsh and speaks welsh and english. he grew up closest to his mother, his muggle parent, and introduced his pureblood best friends to muggle culture.
evan + pandora grew up with basically just them. they were told they were better than everyone for their blood and family, and they became very close. sirius + regulus are very similar in that regard! they absolutely have some level of incest.
remus' favorite musicians were the rolling stones and elton john. sirius' favorites are queen and david bowie.
barty's first crush is on regulus.
