Sociolects are language varieties linked to speakers' social backgrounds, differing from regional dialects (which are geographically based) in vocabulary, grammar, and pronunciation.  While accent focuses solely on pronunciation differences, dialect encompasses all three.  Sociolects often emerge from social, rather than geographical, distance.  A region's perceived lack of development can lead its dialect to be stigmatized and viewed as a sociolect, particularly if speakers migrate to more affluent areas.