“I KNOW you can’t talk. That’s what I like best.” So says Hanna Schygulla’s character Marie in Katzelmacher, Rainer Werner Fassbinder’s second feature film.

She’s addressing Greek “guest worker” Jorgos, played by Fassbinder, who disrupts the lives of an aimless, alienated friendship group in Munich.

Like all of Fassbinder’s films, it sets out to interrogate the prejudices and unspoken crises of post-war German society.

The picture which did so most famously was Fear Eats the Soul, which as the centrepiece of the BFI’s two-month retrospective on the film-maker, is being screened almost every day at the National Film Theatre on London’s Southbank. Unflinchingly, it charts the relationship between an elderly woman and a Moroccan migrant worker in post-war Germany, and there will be few evenings when visceral responses to race, gender, sexuality and revolutionary politics are not on the screens.

Fassbinder, arguably the most significant figure in the New German Cinema movement, worked at a frantic pace before dying aged 37 in 1982.

He used and abused his crew and stock company, a number of whom were also his lovers. He actively courted controversy, and was accused of both misogyny and homophobia over his 1972 picture The Bitter Tears of Petra von Kant (bottom left), in spite of his own bisexuality and the film’s all-female cast.

This film offers his starkest example of muteness, in the character of Marlene, an assistant to Petra, a fashion designer. In a masterly performance by Irm Hermann, Marlene is regularly present but utters not a single word before eventually packing her belongings — including a revolver — to the tune of The Platters’ hit The Great Pretender.

It’s not to diminish the importance of their dialogue, but Fassbinder’s films are often driven by the unsaid. For the unsaid is all too often the unspeakable — the internal and external horrors that these characters and post-nazi society must, but cannot, confront. And thus they spiral out of control.

In a recent newspaper interview Hanna Schygulla, who appears in 17 Fassbinder films and TV dramas, said she questioned the ending of his seminal 1978 film The Marriage of Maria Braun. “I said: ‘Why does she have to die?’,” she recalled. “[Fassbinder] said: ‘Because she’s gone too far. If you go too far, there is no way to turn back.’”

In a Q&A opening the BFI’s season, Schygulla and Juliane Lorenz, Fassbinder’s editor and companion, placed Maria Braun firmly in the context of the failure to make a break with its past after the West German “economic miracle.”

In the year of its release, Fassbinder told an interviewer the present situation was “actually much worse” than fascism “because it’s settling in for the duration.”

The less-known Why Does Herr R Run Amok depicts the struggles of an Everyman in painfully monotonous everyday interactions. Its pacing is uneasy and at times the film seems only semi-committed to its political commentary on late capitalism. It is, of course, inevitable that any director who made over 40 films in 15 years would produce works of varying quality.

But the BFI’s near-complete season allows us to immerse ourselves in the murky and thrilling world of this rapid production line. Seeing the same faces — and, often, highly similar characters — over successive nights is strikingly powerful.

The familiarity of each film’s cast heightens our empathy with the characters. In a film-maker so influenced by melodrama, and in particular the films of Douglas Sirk, this seems no accident.

And yet the actors’ adaptability also serves Fassbinder’s conscious echoes of Bertholt Brecht’s alienation effect.

It’s hard to consider these figures as old friends, especially when their communication is so stilted.

But as we glimpse them as half-forgotten acquaintances in the beer cellars, we can only conclude that Fassbinder was made for a retrospective.

Rainer Werner Fassbinder runs at BFI Southbank until May 31, details: bfi.org.uk