According to research studies, Labov used sociolinguistic interviews to collect formal and informal speech.
William Labov made this research study titled " The social stratification of English in New York City."
The research study was published in 1966.
A sociolinguistic interview is a form of interview designed to gather linguistic data in varying speech situations.
Socio-linguistic interviews usually have both informal sections and formal sections.
Hence, in this case, it is concluded that the correct answer is "sociolinguistic interviews."
Learn more about the sociolinguistic interview here: https://brainly.com/question/13218559
