Just when you thought Bong Joon-ho – the affable maestro of Korean cinema and now, with his class-conscious Cannes winner Parasite, champion of the people – could not get any more lovable, they let him on Jimmy Fallon. Foreign-language arthouse directors rarely, if ever, make it on to US talkshows; this was apparently the first ever Tonight Show interview conducted through an interpreter. With the director cheekily refusing to play ball at points, including breaking down what the film was actually about (“This is a talkshow – you have to say something!” Fallon chided him), the limelight improbably fell on the woman next to him: Sharon Choi.

And Choi scored big. “Bong Joon ho’s translator will u marry me,” trilled one Twitter user. Maybe it was her all-black ensemble and cute Harry Potter specs, or maybe it was the flawless simultaneous translation they found so hot. “So eloquent … so swift … my inspiration,” cooed another. More plaudits: “The MVP [most valuable person] of awards season.” And then the ultimate endorsement: “In every recent Bong Joon-ho Q&A and interview on YouTube, his translator gets praised over and over in the comments. There’s a lot saying she’s one of the best in the world. Major props.”

Louisa Lim (@_louisalim_) Bong Joon Ho's translator is the MVP of this year's awards season #Parasite pic.twitter.com/ROOs0tdjxc

Choi – a 25-year-old Korean-American, also a film-maker, currently living in Seoul – has only been working with Bong since May, when her skills made her an indispensable part of his team at Cannes. But her scene-stealing has shone a light on interpreting, an overlooked aspect of film’s promotional circuit, especially on the arthouse side. It is a high-grade post, combining two-way linguistic expertise, formidable memory skills (good for keeping hold of rambling directorial musings) and a head for PR. Ever-present, as Choi has been as Parasite does the rounds, interpreters sometimes become a mouthpiece for certain directors. The fresh-faced young man that Takeshi Kitano had on hand during junkets in the early 00s was very conspicuous amid the retinue of yakuza-like goons who would hang around the director during his interviews.

Chief responsibility is conveying the precise nuances of what a director wants to communicate about their precious latest work. In that respect, there is surely no more intimidating a client than Michael Haneke. King’s College academic Martin Brady has been his go-to man for years. He has obviously cornered the market in Austrian miserabilists; he works for Ulrich Seidl, too. Not only does Brady manage sparkling English-language renderings of Haneke’s icy existential pensée, but reportedly he also delivers his translations in a light Austrian accent.

The director-interpreter relationship sometimes approaches symbiosis (possibly lulled into this state by the monotonous questioning on press tours). The Oldboy director Park Chan-wook’s interpreter, Jeong Won-jo, has been known to finish in English before Park has in Korean. The pair have an unusually tight partnership, with Jeong – who lived in New Zealand from the age of 12 – functioning as co-producer on Park’s English-language film Stoker and also The Handmaiden. The two jobs are not so far apart, he stresses: “They are both about conveying ideas and building bridges. [They are] to make sure the communication between Park and everyone else was everything it should be: timely and clear.”

Facebook Twitter Pinterest Translator Massoumeh Lahidji with Elia Suleiman at Cannes, 2019. Photograph: John Phillips/Getty Images

Perhaps the gleaming C3PO of cinema interpreters is the Iranian-born, French-based Massoumeh Lahidji, who spent 12 years as a Cannes in-house translator. A self-described “smuggler, or a midwife, helping things to happen”, she works in Farsi, English, French and Spanish – translating for the likes of Pedro Almodóvar, Asghar Farhadi, Martin Scorsese and Werner Herzog. At an Alfonso Cuarón masterclass at last year’s Lumière in Lyon, the festival director Thierry Frémaux gave her a billing almost on a par with the director himself. Lahidji, who came to Paris in 1982 after escaping revolutionary Iran through the Kurdistan mountains, fell into translation after a chance meeting with Abbas Kiarostami at her first Cannes festival. She accompanied him at festivals for the next nine years, subtitled his films and translated the script for 2010’s Certified Copy. She is especially renowned for conducting live translations without taking notes. “A notebook would only get in the way,” she told Le Monde this year. “I prefer to watch a face, the energy a person gives off. I’m custodian of it for a brief instant, then I give it back to the public.”

She calls it the “art of the ephemeral”, but interpreting is also political: helping to level the playing field in cinema. “In a jury, when you have a male American film director, he speaks English and of course he feels much more in power than an actress who’s not comfortable speaking English,” she told AP. Translation is an act of democratisation in a milieu increasingly dominated by English – and it is the reason Bong got to go on Fallon in the first place, something not lost on Sharon Choi’s Twitter stans.

• Parasite is released in the UK on 7 February