Who theorized about negative formation and question formation in child language acquisition?

The correct answer is that Bellugi made significant contributions to the understanding of negative formation and question formation in child language acquisition. Her research involved observing how children develop the ability to form negative statements and questions, revealing distinct stages in their language development.

Bellugi's work highlighted the natural progression children undergo in acquiring these grammatical structures, illustrating how they initially might use simpler forms before mastering more complex sentences. She focused specifically on the ways children manipulate language to convey negation and inquiry, offering insights into their cognitive processes as they navigate language learning.

In contrast, while Piaget's theories focus on cognitive development, Chomsky is known for his universal grammar framework, emphasizing the innate aspects of language. Vygotsky, meanwhile, is often associated with social contexts of learning and the importance of interaction in cognitive development, rather than the specific mechanisms of language structure that Bellugi studied.