You don't read it in the sense of reading a message; it doesn't work like that. What's happening is that the Shadows are responding to the attention you pay them.
Philip PullmanShe found out that having something to do prevented you from feeling seasick, and that even a job like scrubbing a deck could be satisfying, if it was done in a seamanlike way. She was very taken with this notion, and later on she folded the blankets on her bunk in a seamanlike way, and put her possessions in the closet in a seamanlike way, and used 'stow' instead of 'tidy' for the process of doing so. After two days at sea, Lyra decided that this was the life for her.
Philip PullmanEveryone, from the Mother Superior to the priests to my parents--they were so upset and reproachful...I felt as if something they all passionately believed in depended on me carrying on with something I didn't.
Philip PullmanShe was riding a bear! And the Aurora was swaying above them in golden arcs and loops, and all around was the bitter Arctic cold and the immense silence of the North.
Philip Pullman