* Developmental Psychologist: They study cognitive development, including how children learn language, from the first babbles to complex sentences.
* Linguist: They study the structure and function of language, including how it changes over time and across cultures. They could investigate the development of language in individuals or in communities.
* Neuroscientist: They study the brain and its functions, including how the brain processes language. They might investigate how the brain develops language skills or how brain activity differs in language-impaired individuals.
* Speech-Language Pathologist: They work with individuals who have communication disorders, including language delays or impairments. They may research the underlying causes of these disorders and develop interventions to help people improve their language skills.
Ultimately, the specific field of study will depend on the specific questions the researcher wants to answer about language development.