Final answer:
Avia is showing her grasp of pragmatics, which is the aspect of language concerned with its use in social contexts and altering speech to fit different situations.
Step-by-step explanation:
Avia, at 5 years old, is demonstrating her understanding of pragmatics when she talks to her imaginary students in a way that is different from how she typically speaks. Pragmatics relate to the use of language in social contexts and understanding the nuances that alter meaning, such as tone, body language, and the setting in which language is used. Children learn to adapt their speech based on the social situation, an example of which is Avia “playing teacher” by changing her manner of speaking to fit what she understands as the teacher's role.