Final answer:
A dialect is a unique form of a common language associated with different regions and groups, while a subdialect is a further subdivision within a dialect, reflecting more specific variations.
Step-by-step explanation:
Dialect: The term dialect refers to the unique forms of a common language that are associated with different regions and groups. For instance, regional authors often write their dialog in 'New England dialect' or 'Southern dialect.'
Subdialect: A subdialect is a further subdivision of a dialect. It reflects more specific variations within a particular region or social group, such as a neighborhood or a specific ethnicity.
For example, in the United States, the standard American English is a dialect, while African American Vernacular English is a subdialect of that dialect, specific to the African American community.