Borrowing: The adoption of words or other language elements from one language into another language, characteristically with adaptation to the phonology, morphology, and syntax of the adopting language, and frequently with alterations in meaning.
Code-Switching: The use of more than one language, variety, or style by a speaker within an utterance or discourse, or between different interlocutors or situations.
Colloquial: A more technical term for vernacular.
Communication: A fundamental component of social behavior; the transmission of information (messages) between a sender and a receiver using any of the five senses. Language is a form of communication specific to humans.
Creoles: Languages that developed from pidgins by expanding their vocabularies and developing more complex grammatical systems, and that have become the native languages of their speech communities. Creoles are often classified by the language that supplied vocabulary (the "lexifier" language), eg, English creoles and French creoles.
Dialects: Language varieties distinctive of geographically or socially defined groups due to their pronunciation, grammar, vocabulary, and style; usually mutually intelligible to other dialects of that language. Includes standard dialects, nonstandard dialects, idiolects (distinctive of an individual), acrolects (prestigious dialects), basilects (stigmatized dialects), mesolects (dialects neutral as to prestige).
Genetic Classification: The grouping and subgrouping of languages according to hypotheses of genetic relationship, ie, descent from a common ancestral language. Does not imply a hereditary (ie, DNA) component to language.
Language: Regarded as a defining characteristic of being human; a rule-governed system of communication in which basic signals are assembled into more complex messages according to patterns shared by sender and receiver; usually conveyed by vocal sounds but also by gesture (eg, sign language) or visual media (eg, writing). Languages are usually composed of geographically and socially defined dialects that are mutually intelligible.
Language Contact: Interaction between two languages, mediated by individuals who speak both, and the effects over time of such interaction on the phonology, morphology, syntax, and semantics of each language.
Language Standardization: The development of a standard dialect and/or standard written form of a language by language planning, normative instruction, spontaneous change, or other means.
Language Varieties: Systematic variants of the usage of a language determined by individual and/or group characteristics. Includes standard and nonstandard usage, and norms as well as deviations from those norms. All language users speak/sign/write a variety of their language.
Neologisms: Words that have only recently appeared in the lexicon of a language as the result of linguistic creativity or word formation and are not borrowings from another language or dialect.
Nonstandard Dialects: Language varieties that deviate from a commonly accepted language norm.
Pidgins: Contact languages, usually with limited vocabulary and simplified grammatical structure, and no native speakers; typically resulting from the incorporation of vocabulary from one or more languages into a simplified form of another language. Also called contact vernaculars.
Relexification: A process, usually occurring in pidgins and creoles, whereby a language retains the essential components of its grammar but replaces all or part of its lexicon by borrowing from one or more other languages (referred to as lexifiers).
Shibboleth: Language usage indicative of one's regional and/or social origins used to identify members of one's own or of another group. Borrowed from Biblical Hebrew; refers to the story in the Book of Judges 12:5-6 in which shibboleth was used by the Gileadites as a password to identify the Ephraimites by their dialectal pronunciation.
Slang: Informal/popular language usage that functions to establish/reinforce in-group identity and cohesiveness; characteristically specialized, stylized, substandard, and transitory.
Standard Dialects: Any varieties of a language that have gained general acceptance as models to be emulated by all speakers of that language within a particular geographic region, political entity, or social class or group; usually identical to the literary language, and usually the result of language standardization.
Vernacular: Everyday informal language style of a location or group and regarded as native or natural to it; contrasts with more sophisticated, cultivated, or specialized varieties.
Definitions provided with the assistance of the Concise Oxford Companion to the English Language, McArthur, Tom [Ed], Oxford U Press, 1996; and the Thesaurus of Linguistic Indexing Terms (2nd Edition), Colby, Anita, San Diego, CA: Sociological Abstracts, LLC, 1998.