Because you seriously cannot give me one Tamil James Potter headanon and not expect me to worldbuild. You cannot. Here have some rambly headcanons:
The Tamil lineage of the Potter clan are possibly wizarding Iyers (I say possibly because well Tamil surnames *shrug*) that emigrated during the Raj. They adopted the name Potter after a Potter marrying into their family and maybe converted eventually because it made things simpler. But all their other Iyer Tamil customs and traditions remained.
However the Tamil Potter line stayed strictly Tamil (Brahmin - if we’re going to be honest, they were picky about that) for years. They eased off later on, about any kind of purity and were the first branch of the all the Potters to do so.
James mother is a practising Hindu and a classical singer. She thinks her clan is the Pillai clan but her family too emigrated during the Raj so there’s a lot of lost family history. His father is a non practising Christian.
James speaks Tamil at home. He knows more spells in Tamil and Sanskrit than English and Latin.
His parents call him ‘kanna’ at home.
Communication is James’ main issue in Hogwarts because doing so in English all the time is exhausting for him. He constantly code-switches to Tamil without realising it, and then when he does he has to go back and repeat himself in English which frustrates him to no end. He gets much better, but it stays a problem throughout his life at Hogwarts, and is prominent mostly when he’s back from his holidays.
McGonagall knows a little bit of Tamil, and she is the House head, so she tells James that her door is open whenever she needs to rant. He appreciates it immensely.
Sirius and him initially bond over being the two oddball purebloods. Peter and him bond over missing their homes. Everyone bonds with Remus because honestly Remus incites this feeling in them to take care of him, which he always protests and never understands.
James makes it five weeks before sending out a lengthy ranty letter to his mother grumbling about how he’s missing her cooking. He wanted to hold out until Christmas vacations, but it’s his first Deepavali away from home and he’s homesick. Four days later there’s a huge parcel delivered to him. His mother sends him a whole lot of homemade Deepavali sweets and a whole bunch of recipes. His father sends him detailed instructions on exactly how to sneak down to the kitchens and cajole the house elves into making those dishes. (And also a small sympathy note: because son he knows your plight. He can’t live without his wife’s cooking either.)
Sirius and Peter steal most of the sweets, give a Remus a share, and then join James in sneaking down to the kitchens. (Later James’s parents will realise that this may have been what started their child’s prankster streak. They don’t care that much.)
The rest of the Marauders learn Tamil in secret. It’s absolutely frustrating and Sirius and Peter are just done 90% of the time. But James’ reaction the first time he realises that when he code-switched unconsciously and the rest of his friends just followed his lead, is priceless and worth it. Peter actually clicked a picture of it. Remus sent it to the Potters. James’ mom sent them sweets in return.
Also knowing Tamil comes in handy later on whenever they’re planning pranks or excursions. And once they decide to create the Map and become Animagi to give Remus company during his transformations.
By their third year, the Potters send Sirius, Remus and Peter Deepavali gifts and sweets along with James’ cache.
During his fourth year vacations James and his mother finally convince Mr. Potter to visit India. James and his mom go to her native village, and her family temple, and a whole tour of various places. He takes a fuck tonne of pictures and buys a whole lot of stuff for the rest of the Marauders. He comes back to Hogwarts sun burned brown and a slightly nasal twange to his accent, and so so many gifts for the rest of the Marauders. They make a pact to go there together one day, when school is done, so that James can show them this aspect of his world.
James also learns to cook during this time because his mother forces him to learn. He appreciates this fact years later when he can spoil a pregnant Lily. (He never thought she’d like vegetarian food so much.)
The first time Mrs Potter called Sirius ‘kanna’ he might have cried. For hours. James is a good friend who never mentions it.
When Sirius comes to stay with them, he becomes best friends with James’ mom and the two of them chat in rapid fire Tamil for hours.
After Lily and James’ sixth month anniversary Sirius is the one who offers to teach Lily Tamil. While this is how they find out that Lily is gifted with languages, her accent is wrong. Mrs. Potter adores her anyway, and adores Sirius more for teaching her, and James is too busy swooning over the fact that Lily picked up Tamil for him, to bother or notice that his friends are laughing at him.
Even though their wedding is rushed, Lily still wears James’ mother’s bridal sari, instead of a wedding gown. James’ cries the moment he sees it because his mother would’ve wanted it. Sirius is a good enough friend and Best Man to not laugh at him for the rest of his life. (Also, as Remus reminds him later on, because he was crying too. They all were.)
James wanted to take Lily to his mother’s native village in India too. She said when the war was over they’d go, and drag their friends too.
Once Harry bonds with them, finally after years, Remus plans to teach him Tamil. Sirius searches everywhere for Mrs Potter’s recipe book, and the various other recipes he knows he had. Because both of them hate the knowledge that Harry has grown up without his culture, something James took a deep pride in. They know that if Harry grew up with James and Lily, this is what he’d have grown up with, and they want him to have a taste of that.
The fact that it doesn’t happen because of fucking Voldemort will be a regret that both men take to their graves.
When the War is over Ginny is the one who finds Mrs Potters recipe book. She shows it to the Trio. Hermione goes out to find books that will teach them Tamil, (emphasis them) because while it may not be the dialect Harry would have learned but it is something. Harry’s emotional over the whole thing, and Ron awkwardly consoles him.
This also spurs Harry into digging into his family traditions. Ginny encourages him because she knows how important those are.
Harry and Ginny go to Mrs Potters native village eventually. Harry comes back tanned and delighted and Ginny comes back with far more freckles, and a bunch of sarees.
The Potter-Weasley and extended family speak Tamil at home eventually.
The first time James Sirius curses in Tamil near McGonagall, she sends Harry a letter telling him that his son sounds exactly like his namesake when he was a child.
Ginny frames the letter on the wall.
