Final answer:
In sociolinguistics, progressive assimilation is when a sound is influenced by a preceding sound, while regressive assimilation is when a sound is affected by a following sound. Assimilation in a sociocultural context is measured by benchmarks related to socioeconomic status, language, and other factors.
Step-by-step explanation:
The question What is the difference between regressive and progressive assimilation? appears to be mixed up with another topic line that deals with linguistic assimilation, which is a part of sociological study. However, in sociolinguistics, progressive and regressive assimilation refer to phonological processes affecting speech sounds. Progressive assimilation happens when a sound is influenced by a preceding sound, whereas regressive assimilation happens when a sound is influenced by a following sound. Assessing cultural assimilation involves benchmarks like socioeconomic status, spatial concentration, language assimilation, and intermarriage.
Other terms that could be used to represent these processes in sociolinguistics could include 'anticipatory assimilation' for regressive assimilation, as the change anticipates the upcoming sound, and 'preservative assimilation' for progressive assimilation, as the preceding sound influences the following one.