Talking clearly wasn't working. The Doctor reached out and and gently placed a hand on John's elbow. He had an idea of where John's thoughts had gone; there was no need for telepathy to figure that much out.
"You studied. Maybe not exactly as you remember, but you did. You studied with other children at an academy. You had a family. You had a home. Your life wasn't simply invented from scratch. Do you remember when Joan asked you where you learned to draw, and you told her Gallifrey? That was real. It was the truth. You learned where I learned."