But the one thing he does more noticeably, and perhaps more often, than any other activity is grunt.
It is a scratchy but rich sound, a no-holds-barred burst of gutteralism, made in response to any number of comments or actions by the people around him. It suggests as many things as he wants it to convey, or as the viewer wants it to convey.
"Grunting grew instinctively from this emotional man who had a million things to say but never said them," Spall explained to reporters at the festival Thursday afternoon. "So he encapsulated it with this burning grunt."
Perhaps best known to mainstream audiences as Peter Pettigrew in the "Harry Potter" movies, Spall gives a full-throated performance in more ways than one in "Mr. Turner," Leigh's chronicle of the last 30 years in the life of the Romantic painter. To those who know the British Spall primarily as a character actor — he has been in several other Leigh works, including award-season hit "Secrets & Lies" — this will cast him in a new light. It's the kind of performance that will have awards pundits putting him on early Oscar shortlists.
The movie, which Sony Pictures Classics will release later this year, is a realization of a long-held Leigh dream; he's been wanting to make it for more than a decade, telling the Los Angeles Times an interview as far back as 2010 that he was finally close.
To some fans the movie will evoke another of Leigh's period examination of artists, 1999's Gilbert and Sullivan dramatization "Topsy Turvy," also starring Spall (and examined by my colleague Kenneth Turan at the time).
One can understand why both director and star were so enamored.
As the carefully paced film unfolds, Turner emerges as a great artist and complicated person, a man with voracious appetites and a penchant for extremism. He is something of a tragic figure, one who pushes away many around him, for reasons that are sometimes understandable and sometimes inexplicable. When some love does come into his life, he's not always sure how to handle it.
Spall said he found a lot to explore in the dark character.
"What made us a perfect match is that he was a funny looking fatty old man and so am I," the actor, 57, joked. Then, turning serious, Spall added that as he began to research Turner, he found a deep layer of meaning.
"It became obvious to me that genius is not always in the romantic of packages. Most geniuses are strange -- they are often odd-looking sociopaths," he said, adding, "this man was kind of simian, kind of apelike. He was working-class but he had this amazing soul."
Spall said he learned to paint working with some talented pros for two years before the six-month rehearsal process with Leigh began. (The Brit made this film as he does all others, beginning with no script but working it up over the many weeks of preparation with his actors.)
As Turner finds success he also doesn't quite find happiness, or at least conventional notions of it. He turns down a major offer for his work in the name of either noble or dubious idealism, as questions about greatness and its costs come into focus. One of the main themes of the film is the balance between the creative and the banal, the artistic and the everyday.
Leigh described it at the news conference as "the tension between this very mortal, in some ways flawed, and very inspired individual and this epic work."