Regional dialects are variations of a language that differ based on geographic region. They can vary in pronunciation, word choices, and grammatical rules. Examples include different pronunciations of words like "luxury" between American and British English. Regional dialects also vary lexically, with different words used to refer to the same objects in different places. Additionally, regional dialects exhibit syntactic differences, such as the use of double modals or objects in some areas. Social dialects arise from social factors and can be based on socioeconomic status, ethnicity, gender, and other social attributes.