When I attempted Speaker for the Dead for the first time back in 6th grade, shortly after finishing Ender's Game, I'll admit that most of it went over my head. I understood the basics of the Lusitanian colony life, the interactions among the Piggies and the external threats all were facing, but I simply didn't have the life experience to appreciate the bigger themes. I knew what a Speaker for the Dead did; I did not understand what a Speaker for the Dead was for. It would take two more attempts before I "got it." And now—some decades and countless philosophical discussions later—I can claim that Speaker has affected me in profound ways that would have been impossible when I was younger.
To change things up I listened to the audiobook on this last re-read, and at the end Card gives this interview where he provides a little background on how the story came about. He relates an anecdote about when he was a Mormon missionary in Brazil attending a funeral for a man who was an abusive husband, and how his victimized wife openly and unabashedly mourns upon his coffin. You'll have to hear it. It wasn't that this story was particularly sad, but I'm nearly moved to tears by the end. There was a part about "To understand someone, even one who has done wrong to you, is to love them." It's arguably THE central theme of both Ender's Game and Speaker. Have you ever been exposed to an idea that your heart understood right away but would take your mind days, months or even years to grasp?
The irony is that in the past few years Orson Scott Card has earned public derision for being intolerant of homosexuality and for espousing a slew of bigoted ideas—ideas I certainly do not share. Meanwhile, I've been a committed atheist/agnostic for over almost two decades. And yet here we are, meeting in the middle on the shakiest of common ground, able to share this one enlightened idea.