to tell a story-possibly as the main voice in a documentary; or a character who speaks to the audience in a performance
The specific meaning of narrate depends on context. For example:
"She narrated her story with tears in her eyes." — told a story
"Her diary chillingly narrates her descent into madness." — tells a story in writing
"Morgan Freeman narrated the documentary which features historic news reports and interviews." — was the voice that tells a story while tying the scenes of a documentary together
"The character who plays the Stage Director in Our Town also narrates for the audience." — when an actor in a play, movie, or other performance helps to tell the story by talking directly to the audience (breaking the imaginary barrier between the performers and the audience)
It is, as Bruner and Joan Lucariello write in their commentary on the segment, a remarkable act of world making... she uses tonal emphasis, prolongation of key words, and a kind of "reenactment" reminiscent of the we-are-there cinema verite (with her friend Carl practically narrated through the door as he enters).
Chapter 3 (74% in)
There are no more uses of "narrate" in The Tipping Point.