For Ishmael names are personal, and he has been a part of a larger group for so long that he has forgotten about his own identity..... the boy he really is. In getting Ishmael to say his own name aloud, Esther also puts herself in a position to introduce herself.... to make it personal.
An example of someone not giving Ishmael and Kanei his name can be found in Chapter Eight. The old man didn't answer because he no longer mattered.... he believed himself to be just one person out of many to be left behind, and he was accurate in his belief..... he was one of the many, another casualty in the war.
“What is your name?” Kanei asked the old man.
He smiled as if he knew that one of us would ask this question. “There is no need to know my name. Just refer to me as the old man who got left behind when you get to the next village.” He looked at all our faces and spoke softly, with no sadness in his voice. “I will not be alive to see the end of this war. So, to save a place in your memories for other things, I won’t tell you my name. If you survive this war, just remember me as the old man you met. You boys should be on your way.”