Alliteration is used to describe the soldier.
Alliteration is a sound device where the initial sounds of words are repeated. It can be used to add a poetic quality to writing. Although some alliteration can be incidental, it is often done purposely to call attention to the words.
Here is an example from Chapter 1. When the soldier is described, he is described as stern. Even though there are words in between, the repetition of the “s” sound to describe the solider is purposeful. A better example is the description of Annemarie’s reaction to the word the soldier uses.
"Halte!"the soldier ordered in a stern voice.
The German word was as familiar as it was frightening. Annemarie had heard it often enough before, but it had never been directed at her until now. (Ch. 1)
The use of alliteration here accentuates the mood. We can tell that Annemarie is afraid. We also know that encounters with German soldiers are common, but that does not make them any less scary.
Here is one more example.
Behind her, Ellen also slowed and stopped. Far back, little Kirsti was plodding along, her face in a pout because the girls hadn't waited for her. (Ch. 1)
The author intentionally repeats the “s” sound again, like the repetition of the “f” sound above. In this case, the pattern adds to the suspense of the scene. The reader is wondering what is going to happen between the three girls and the solider.
This incident establishes the setting well for the book. We learn about the presence of German soldiers in Denmark during World War II, and it also foreshadows the situations that Annemarie will be put in during the course of events in the book. This is the first incident in which the war hits home, but there will definitely be many more for her.