An infant whose family dog is named “Ralph” refers to all four-legged animals (e.g., cats, cows, horses) as “Ralphies.” This is an example of:

This example illustrates the concept of overextension in language development. Overextension occurs when a child applies a word they have learned (in this case, "Ralph") to a broader category of objects or animals than the term specifically refers to. In this scenario, the infant uses “Ralph” (the family's dog) to label not just their dog but all four-legged animals, which is a common occurrence in early language acquisition. It reflects the child's attempt to make sense of the world and categorize it based on their limited vocabulary and experiences. Overextension is a natural part of language development as children learn and refine their understanding of language.