Sociolinguistics is a scientific field that comes from linguistic and sociology and defined as the study of the influence of society on language, including cultural norms, expectations and the context in which the speakers are living.
Study the difference between the sociolect groups separated by certain social variables such as religion, educational level, socioeconomic level, the source of the speaker (for example, city-country). When this is coupled with a particular culture sometimes it is called etnolect, for example, yidis is usually regarded as a German dialect.
The use of such language varieties can be used to categorize individuals in social and socio-economic classes, even if the same individual may use different varieties of language according to the social situation and the context in which he interacts.
We would say that Sociolinguistics covers dialectology, in first instance, then study the various combinations: it start from the me, but immersed in the society. For example, a sociolinguist could determine through using social attitudes in the use of slang may be considered inappropriate in certain contexts professional in Argentina, could also study the grammar, phonetics, vocabulary and other aspects of this sociolecto, while a dialectólogo studying the geographic variation of the language.