What does the nativist model help to explain?

The nativist model is primarily focused on the innate aspects of language development, positing that humans are born with a biological ability to acquire language. This model helps to explain how people can understand and produce a seemingly infinite number of linguistic expressions because it argues that children possess an inherent capacity, often referred to as a "language acquisition device." This device allows them to recognize the underlying structures and rules of language, leading to the ability to generate an unlimited variety of sentences, including those they have never encountered before.

In contrast, approaches that focus on reading and writing or that emphasize social interaction and environmental factors do not address the innate cognitive mechanisms that the nativist model highlights. These elements are more concerned with the development of language skills through external influences rather than innate abilities. Therefore, the correct answer accurately reflects the primary contribution of the nativist perspective in understanding the complexities of language production and comprehension.