Anna and the Swallow Man by Gavriel Savit
In 1939 it’s just Anna and her father, a linguist who speaks a different language to Anna every day of the week. Then he is gone, a victim of the German purge of Polish intellectuals. Anna is just seven years old.
She meets the Swallow Man, a man who also speaks many languages, including the language of birds, which he uses to soothe Anna. She sees in him protection and survival, though it will mean spending years roaming the forests. He doesn't want her with him, she is a liability to his survival and ability to melt into nothingness but even The Swallow Man can't abandon a seven year old child. The two learn to speak little.
As this story is told we learn there is much to be afraid of in this world gone mad, bombs, soldiers, people, but a strange man, a little girl and an unlikely friend sometimes work magic, and sometimes they don’t. Sometimes we learn we must fear everyone a little.
This book goes deep, is going to be compared to The Book Thief and will sustain discussion for hours. Days, even.