Speech Community

Speech community is a group of people who share a set of norms and expectations regarding the use of language. Speech communities can be members of a profession with a specialized jargon, distinct social groups like high school students or hip hop fans , or even tight-knit groups like families and friends. In addition, online and other mediated communities, such as many internet forums, often constitute speech communities. Members of speech communities will often develop slang or jargon to serve the group's special purposes and priorities. Exactly how to define speech community is debated in the literature. Definitions of speech community tend to involve varying degrees of emphasis on the following

• Shared community membership

• Shared linguistic communication

However, the relative importance and exact definitions of these also vary. Some would argue that a speech community must be a 'real' community, i.e. a group of people living in the same location  while more recent thinking proposes that all people are indeed part of several communities (through home location, occupation, gender, class, religious belonging, and more), and that they are thus also part of simultaneous speech communities.
Similarly, what shared linguistic communication entails is also a variable concept. Some would argue that a shared first language, even dialect, is necessary, while for others the ability to communicate and interact (even across language barriers) is sufficient.
The underlying concern in both of these is that members of the same speech community should share linguistic norms. That is, they share understanding, values and attitudes about language varieties present in their community. While the exact definition of speech community is debated, there is a broad consensus that the concept is immensely useful, if not crucial, for the study of language variation and change.

History of The Concept
The adoption of the concept speech community as a focus of linguistic analysis emerged in the 1960s. This was due to the pioneering work by William Labov, whose studies of language variation in New York City and Martha's Vineyard laid the groundwork for sociolinguistics as a social science. His studies showed that not only were class and profession clearly related to language variation within a speech community ,but that socio-economic aspirations and mobility were also of great importance.
Prior to Labov's studies, the closest linguistic field was dialectology, which studies linguistic variation between different dialects. The primary application of dialectology is in rural communities with little physical mobility. Thus, there was no framework for describing language variation in cities until the emergence of sociolinguistics and the concept of speech community, which applies to both rural and urban communities.
Since the 1960s a number of studies have been performed that have furthered our knowledge about how speech communities work and extended its use. Notable sociolinguists who have worked on speech communities include William Labov, John J. Gumperz, Lesley Milroy, Robin Lakoff, and Penelope Eckert.

Language Variation
The notion of speech community is most generally used as a tool to define a unit of analysis within which to analyse language variation and change. Stylistic features differ among speech communities based on factors such as the group's socioeconomic status, common interests and the level of formality expected within the group and by its larger society.
In Western culture, for example, employees at a law office would likely use more formal language than a group of teenage skateboarders because most Westerners expect more formality and professionalism from practitioners of law than from an informal circle of adolescent friends. This special use of language by certain professions for particular activities is known in linguistics as register; in some analyses, the group of speakers of a register is known as a discourse community, while the phrase "speech community" is reserved for varieties of a language or dialect that speakers inherit by birth or adoption.