Spike Jonze has his top button done up and is wearing a chic grey blazer only an unashamed hipster would choose with that particular shirt. "I'm a little slow, so forgive me if I'm inarticulate," he says.
The 44-year-old's low, croaking voice might give the impression he has a bad head cold if it didn't always sound like that. "Forgive me if I fall asleep and drool on the table," he says. He's smiling. He's also doing that thing with a pencil where you spin it around the back of your thumb and catch it with your forefinger.
You wouldn't call Jonze a born salesman of his films, but that's part of his charm.
Released here on Valentine's Day and nominated for five Oscars, including Best Picture and Screenplay, his latest, Her, is a richly poignant near-future romance in which the most functional relationship on screen is that between a sweet loner (Joaquin Phoenix) and his operating system.
Imagine Sleepless in Seattle if Meg Ryan were replaced with, say, Windows Vista. But the conceit is just the tip of the iceberg: it's a gorgeous, insinuating mood piece about the predicament we're all in, spending more time with our web-enabled devices than with our loved ones.
Jonze, particularly in his two collaborations with screenwriter Charlie Kaufman, has a history of choosing male heroes who are nerdy, creatively frustrated, and can't quite express what they want, from John Cusack in Being John Malkovich (1999) to Nicolas Cage in Adaptation (2002) and beyond.
Theodore Twombly, Phoenix's character, is a little more serene, but somehow still the saddest of the lot. Kaufman may have given those other guys their hectic, neurotic patter and sweaty self-consciousness, but there's something of Jonze in them, too: he offers up about 10 possible ideas in response to each question.
Here's what I mean. While shooting this film, Jonze was also working nights in a writer-producer capacity on the Jackass comedy feature Bad Grandpa, which is typical Jonze – by day, facing up to the loneliness of the post-modern condition; by night, putting aged-up Johnny Knoxville in a pair of baggy Y-fronts and sending him into an all-black male strip club.
"Ideally it wasn't, it was, ideally it wasn't, it wouldn't have been at the exact same time," he says in his endearingly staccato way. "That actually made it hard. But it certainly was fun to just be able to just go, and. . . Yeah, switching gears, and just like go, go sit with my old friends, and, you know, just make each other laugh, and come up with ideas, and look at footage, and laugh."
The way Jonze speaks makes you realise that his films – those he directs, at least – are all about communication, and often about things coming out the wrong way.
There's that wonderful moment in Adaptation where Nicolas Cage tries to introduce himself to Meryl Streep in a lift, and can only blurt out a kind of strangled half-syllable – "Ka ... " – which she pretends not to hear. That sound sums up the nuance and wit of Jonze's direction – it's not in Kaufman's shooting script. It's not impossible that Jonze and Kaufman could work together again soon, but for the time being, they are both going solo. Her, which comes from the first screenplay Jonze has written by himself, is precisely about hiding away in our own private shells, and getting other people to communicate for us.
Theodore's job is sending out heartfelt little epistles for people too busy or emotionally numb to make the effort.
It's here that he starts to bond with his new computer, which comes with a state-of-the-art voice interface called Samantha, to which Scarlett Johansson supplies her unmistakable husky tones.
Jonze claims that the idea for the Theodore-Samantha relationship came from a brief moment he had on his smartphone. "It was this very limited interaction with a programme, an instant messaging chat. Then Siri [Apple's personalised user interface, launched in 2011] came out as I was writing this. It seemed like a good sign."
The name Siri comes from a Norwegian term that means, "beautiful woman who leads you to victory", which is very much the effect Samantha has on Theodore.
But there are other significant women in Theodore's orbit who have the disadvantage of being human. They're played in the movie by Amy Adams, Rooney Mara and Olivia Wilde.
One man's fragmented love life is a complicated thing to juggle on screen, even over 126 minutes, and it's not surprising that Jonze spent a long spell – more than a year – finding this film in the edit.
The single-most pivotal decision in post-production was to recast the role of Samantha, which had already been fully recorded by Samantha Morton. Jonze has explained that the character needed a more familiar, come-hither quality in her vocal timbre.
Replacing Morton was a tough call. She keeps an associate producer credit, and the character retains her name, but even beyond these gestures, it's not as if her work has left no trace on the finished film.
After all, Phoenix's whole performance is an interaction with Morton's line readings, not Johansson's – a strangely appropriate disconnect for a film intentionally full of them.
Jonze also asked some old friends to look at the film in its rough-cut form – David O Russell, and Steven Soderbergh, who handed back his own radical cut within 24 hours. "I was hoping for him to shock us," says Jonze.
Soderbergh, true to that remit, slashed the film in half, rearranging scenes and forging some new connections that made their way into Jonze's final cut.
Jonze says he only knew Phoenix "in passing" before realising he'd be perfect for this role – which he is. "I went to his house and offered it to him just to see what he was like," says Jonze. "Within five minutes I fell in love with the idea of him being in the movie. Then we started rehearsing together, reading the script over and over and over again.
"We'd spend five days at a time, and I'd go off and write for a few months, then we'd meet up again. In that year, we got to know each other really well. So, by the time we were on set, we already had like a second, a second-hand, what's it called?" A shorthand? "A shorthand, or second nature!" He grins, loving his fumble. "We had a second nature!"
Does he think he'll keep up that other, pranksterish persona as a Jackass producer, which feels like a direct link back to his filmmaking origins? Even as I ask, I know that Jonze won't want to pin himself down.
He does a kind of coy squirming routine. "Maybe. Maybe? I don't know. Maybe not. I don't have any plans. I just want to be who I am, as I am."
'HER' IS OUT ON FEBRUARY 14