A kindergarten teacher reads a decodable text about cats with a small group of students and then incorporates the content of the text into an interactive writing lesson. First, the teacher has students orally generate several sentences that relate to the actions of the cat in the story. The teacher then says, "Those are great sentences. Help me write them on the chart paper." For each decodable word in a sentence, the teacher pauses to prompt the students to listen to the sounds of the word and use their knowledge of the letter-sound correspondences that they practiced in the decodable text to identify which letter the teacher should write next. This scenario best demonstrates the teacher's awareness of which of the following concepts related to students' development of beginning reading skills?