<Table> <Tr> <Th> Sociolinguistics </Th> </Tr> <Tr> <Th> Key concepts </Th> </Tr> <Tr> <Td> <Ul> <Li> Code - switching </Li> <Li> Diglossia </Li> <Li> Language change </Li> <Li> Language ideology </Li> <Li> Language planning </Li> <Li> Multilingualism </Li> <Li> Prestige </Li> </Ul> </Td> </Tr> <Tr> <Th> Areas of study </Th> </Tr> <Tr> <Td> <Ul> <Li> Accent </Li> <Li> Dialect </Li> <Li> Register </Li> <Li> Discourse analysis </Li> <Li> Language varieties </Li> <Li> Linguistic description </Li> <Li> Pragmatics </Li> <Li> Variation </Li> </Ul> </Td> </Tr> <Tr> <Th> People </Th> </Tr> <Tr> <Td> Sociolinguists </Td> </Tr> <Tr> <Th> Related fields </Th> </Tr> <Tr> <Td> <Ul> <Li> Applied linguistics </Li> <Li> Historical linguistics </Li> <Li> Linguistic anthropology </Li> <Li> Sociocultural linguistics </Li> <Li> Sociology of language </Li> </Ul> </Td> </Tr> <Tr> <Td> <Ul> <Li> </Li> <Li> Linguistics portal </Li> </Ul> </Td> </Tr> <Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> </Table> <Tr> <Th> Sociolinguistics </Th> </Tr> <Tr> <Th> Key concepts </Th> </Tr>

Write a note on language varieties according to use and region