How does Theodora Kroeber use imagery in Ishi: Last of His Tribe?

Imagery:

After each meal, Tushi spread the salmon bones on a mat in the sun until they were dry. Then she put them in a stone mortar and ground them to flour.

Now the unsaid words poured out faster than the Stranger could mark them down or find them in his lists: words of loneliness, of searching, of hunger, of cave-living alone.