“All Is True” is an ironic title for a historical movie in which virtually everything is made up.

The title, an alternate one for William Shakespeare’s “Henry VIII,” hints at the mysteries about which this drama by director and star Kenneth Branagh speculates, because we know almost nothing about the GOAT playwright: Why didn’t he write anything in the last three years of his life? How did Shakespeare’s young son, Hamnet, die? What were Shakespeare’s relationships like with his two daughters and illiterate wife (Judi Dench)?

And, finally, what would Branagh look like if he borrowed Ben Kingsley’s nose?

A fake schnoz significantly alters Branagh’s appearance as the Bard of Avon, but his career-long interest in Shakespeare shines through. The mournful and, it should be said, extremely slow-moving story explores Shakespeare’s grief, as a result of his beloved boy’s death and his growing awareness that, in his devotion to his son, he neglected the women of his household, to the point that he’s unaware that one of his daughters has inherited his way with words.

The movie is lovely to listen to, with frequent Branagh collaborator Patrick Doyle’s piano-based score. And it’s pleasant to look at, with cinematographer Zac Nicholson’s (“The Death of Stalin”) lush images of wildflower-packed meadows at dawn and interior scenes illuminated only by candlelight. They give the movie a kind of serenity that is in marked contrast to the fireworks in Will’s home, where his family members can no longer conceal their resentment at being ignored, and in a courtroom, where a vengeance-seeking neighbor is bent on besmirching the Shakespeare name.

But the script by Ben Elton (the “Blackadder” TV series) gets hung up on speechifying and attempts to make connections to well-known plays that force Will to quote himself at length, a no-no that is the gross theatrical equivalent of a rocker wearing his own band’s T-shirt. Elton also has trouble finessing the things-we-know-now-that-they-didn’t-know-then aspect of a historical drama, so the proto-feminism of Shakespeare’s daughter feels forced and a prediction that his work will live forever comes off as phony.

The script is best in its quiet moments, such as one in which Branagh and Ian McKellen, as a visiting nobleman, exchange barbs, or a tender one in which a melancholy Shakespeare, haunted by his son’s ghost, tells his wife, “Anne, he was here,” and she replies, “He’ll always be here, Will.” Branagh treads lightly on the idea that a man who is haunted by the ghost of his son flips one in “Hamlet,” in which the title character — whose name, of course, is quite similar to Hamnet — is visited by his late father.

The family dynamics and grief of the worthy-but-dull “All Is True” often recall “Hamlet,” in fact, but what’s missing is anything approaching the beauty of Shakespeare’s language.