One of the most powerful forces in a room can be the thing that is unspoken between people. Five writers—Scott Carrier, David Sedaris, Sarah Vowell, Brady Udall and Lan Samantha Chang—give us case examples: stories when they felt the presence of something unspoken.

There's a famous William Carlos Williams poem called "This is Just to Say." It's about, among other things, causing a loved one inconvenience and offering a non-apologizing apology. It's only three lines long, you've probably read it...the one about eating the plums in the icebox.

Host Ira Glass talks about the surprising way apologies tend to play out in couples when one person has cheated on the other, based on stories his mother, Dr. Shirley Glass, told in her book Not Just Friends. And contributing editor Sarah Vowell tells us about the time she couldn't stop apologizing.

Sarah Vowell and her twin sister Amy re-trace the Trail of Tears. They visit the town in Georgia that was the capital of the Cherokee Nation before the Cherokee were expelled.

Sarah Vowell and her twin sister, Amy, retrace the Trail of Tears. They visit the town in Georgia that was the capital of the Cherokee Nation before the Cherokee were expelled. They enjoy a tourist trap hotel in Chattanooga. They go to Ross's Landing, the embarkment point for the water route of the Trail of Tears. (27 minutes)

Sarah Vowell examines what happens when TV takes on a subject it really has no business exploring at all, but seems fairly obsessed with nonetheless: The Pilgrims. Sarah's most recent book is Assassination Vacation.

Sarah Vowell tells the lost story behind a patriotic song, "The Battle Hymn of the Republic." An early version of the song celebrated an American terrorist. She's accompanied by Jon Langford and the band.

Sarah Vowell visits four Presidential libraries on a fact-finding tour for...President Clinton. Not that he asked her.

Here in America, here's how we interact with our political candidates: We dispatch middlemen to the scene, they listen to what the candidates say, they research the candidates' backgrounds, and they tell us what they think is most important. Those middlemen, of course, are journalists.