LANGUAGE VARIETIES
Languages constantly undergo changes, resulting in the development of different varieties of the languages.

A Dialects A dialect is a variety of a language spoken by an identifiable subgroup of people. Traditionally, linguists have applied the term dialect to geographically distinct language varieties, but in current usage the term can include speech varieties characteristic of other socially definable groups. Determining whether two speech varieties are dialects of the same language, or whether they have changed enough to be considered distinct languages, has often proved a difficult and controversial decision. Linguists usually cite mutual intelligibility as the major criterion in making this decision. If two speech varieties are not mutually intelligible, then the speech varieties are different languages; if they are mutually intelligible but differ systematically from one another, then they are dialects of the same language. There are problems with this definition, however, because many levels of mutual intelligibility exist, and linguists must decide at what level speech varieties should no longer be considered mutually intelligible. This is difficult to establish in practice. Intelligibility has a large psychological component: If a speaker of one speech variety wants to understand a speaker of another speech variety, understanding is more likely than if this were not the case. In addition, chains of speech varieties exist in which adjacent speech varieties are mutually intelligible, but speech varieties farther apart in the chain are not. Furthermore, sociopolitical factors almost inevitably intervene in the process of distinguishing between dialects and languages. Such factors, for example, led to the traditional characterization of Chinese as a single language with a number of mutually unintelligible dialects.

Dialects develop primarily as a result of limited communication between different parts of a community that share one language. Under such circumstances, changes that take place in the language of one part of the community do not spread elsewhere. As a result, the speech varieties become more distinct from one another. If contact continues to be limited for a long enough period, sufficient changes will accumulate to make the speech varieties mutually unintelligible. When this occurs, and especially if it is accompanied by the sociopolitical separation of a group of speakers from the larger community, it usually leads to the recognition of separate languages. The different changes that took place in spoken Latin in different parts of the Roman Empire, for example, eventually gave rise to the distinct modern Romance languages, including French, Spanish, Portuguese, Italian, and Romanian.

In ordinary usage, the term dialect can also signify a variety of a language that is distinct from what is considered the standard form of that language. Linguists, however, consider the standard language to be simply one dialect of a language. For example, the dialect of French spoken in Paris became the standard language of France not because of any linguistic features of this dialect but because Paris was the political and cultural center of the country.

B Social Varieties of Language Sociolects are dialects determined by social factors rather than by geography. Sociolects often develop due to social divisions within a society, such as those of socioeconomic class and religion. In New York City, for example, the probability that someone will pronounce the letter r when it occurs at the end of a syllable, as in the word fourth, varies with socioeconomic class. The pronunciation of a final r in general is associated with members of higher socioeconomic classes. The same is true in England of the pronunciation of h, as in hat. Members of certain social groups often adopt a particular pronunciation as a way of distinguishing themselves from other social groups. The inhabitants of Martha's Vineyard, Massachusetts, for example, have adopted particular vowel pronunciations to distinguish themselves from people vacationing on the island.

Slang, argot, and jargon are more specialized terms for certain social language varieties usually defined by their specialized vocabularies. Slang refers to informal vocabulary, especially short-lived coinages, that do not belong to a language's standard vocabulary. Argot refers to a nonstandard vocabulary used by secret groups, particularly criminal organizations, usually intended to render communications incomprehensible to outsiders. A jargon comprises the specialized vocabulary of a particular trade or profession, especially when it is incomprehensible to outsiders, as with legal jargon.

In addition to language varieties defined in terms of social groups, there are language varieties called registers that are defined by social situation. In a formal situation, for example, a person might say, “You are requested to leave,” whereas in an informal situation the same person might say, “Get out!” Register differences can affect pronunciation, grammar, and vocabulary.

C Pidgins and Creoles A pidgin is an auxiliary language (a language used for communication by groups that have different native tongues) that develops when people speaking different languages are brought together and forced to develop a common means of communication without sufficient time to learn each other's native languages properly. Typically, a pidgin language derives most of its vocabulary from one of the languages. Its grammatical structure, however, will either be highly variable, reflecting the grammatical structures of each speaker's native language, or it may in time become stabilized in a manner very different from the grammar of the language that contributed most of its vocabulary. Historically, plantation societies in the Caribbean and the South Pacific have originated many pidgin languages. Tok Pisin is the major pidgin language of Papua New Guinea. Both its similarities to and its differences from English can be seen in the sentence “Pik bilong dispela man i kam pinis,” meaning “This man's pig has come,” or, more literally, “Pig belong this-fellow man he come finish.”

Since a pidgin is an auxiliary language, it has no native speakers. A creole language, on the other hand, arises in a contact situation similar to that which produces pidgin languages and perhaps goes through a stage in which it is a pidgin, but a creole becomes the native language of its community. As with pidgin languages, creoles usually take most of their vocabulary from a single language. Also as with pidgins, the grammatical structure of a creole language reflects the structures of the languages that were originally spoken in the community. A characteristic of creole languages is their simple morphology. In the Jamaican Creole sentence “A fain Jan fain di kluoz,” meaning “John found the clothes,” the vocabulary is of English origin, while the grammatical structure, which doubles the verb for emphasis, reflects West African language patterns. Because the vocabularies of Tok Pisin and Jamaican Creole are largely of English origin, they are called English-based.