Sociolinguistics in the context of "Language policy"

Language change is the process of alteration in the features of a single language, or of languages in general, over time. It is studied in several subfields of linguistics: historical linguistics, sociolinguistics, and evolutionary linguistics. Traditional theories of historical linguistics identify three main types of change: systematic change in the pronunciation of phonemes, or sound change; borrowing, in which new features (often, new words) enter a language or dialect as a result of influence from another language or dialect; and analogical change, in which the shape or grammatical behavior of a word is altered to more closely resemble that of another word. Research on language change generally assumes the uniformitarian principle—the presumption that language changes in the past took place according to the same general principles as language changes visible in the present.

Language change usually does not occur suddenly, but rather takes place via an extended period of variation, during which new and old linguistic features coexist. All living languages are continually undergoing change. Some commentators use derogatory labels such as "corruption" to suggest that language change constitutes a degradation in the quality of a language, especially when the change originates from human error or is a prescriptively discouraged usage. Modern linguistics rejects this concept, since from a scientific point of view such innovations cannot be judged in terms of good or bad. John Lyons notes that "any standard of evaluation applied to language-change must be based upon a recognition of the various functions a language 'is called upon' to fulfil in the society which uses it".

Prestige in sociolinguistics is the level of regard normally accorded a specific language or dialect within a speech community, relative to other languages or dialects. Prestige varieties are language or dialect families which are generally considered by a society to be the most "correct" or otherwise superior. In many cases, they are the standard form of the language, though there are exceptions, particularly in situations of covert prestige (where a non-standard dialect is highly valued). In addition to dialects and languages, prestige is also applied to smaller linguistic features, such as the pronunciation or usage of words or grammatical constructs, which may not be distinctive enough to constitute a separate dialect. The concept of prestige provides one explanation for the phenomenon of variation in form among speakers of a language or languages.

The presence of prestige dialects is a result of the relationship between the prestige of a group of people and the language that they use. Generally, the language or variety that is regarded as more prestigious in that community is the one used by the more prestigious group. The level of prestige a group has can also influence whether the language that they speak is considered its own language or a dialect (implying that it does not have enough prestige to be considered its own language).

Historical linguistics, also known as diachronic linguistics, is the scientific study of how languages change over time. It seeks to understand the nature and causes of linguistic change and to trace the evolution of languages. Historical linguistics involves several key areas of study, including the reconstruction of ancestral languages, the classification of languages into families, (comparative linguistics) and the analysis of the cultural and social influences on language development.

This field is grounded in the uniformitarian principle, which posits that the processes of language change observed today were also at work in the past, unless there is clear evidence to suggest otherwise. Historical linguists aim to describe and explain changes in individual languages, explore the history of speech communities, and study the origins and meanings of words (etymology).

Varieties of Arabic (or dialects or vernaculars) are the linguistic systems that Arabic speakers speak natively. Arabic is a Semitic language within the Afroasiatic family that originated in the Arabian Peninsula. There are considerable variations from region to region, with degrees of mutual intelligibility that are often related to geographical distance and some that are mutually unintelligible. Many aspects of the variability attested to in these modern variants can be found in the ancient Arabic dialects in the peninsula. Likewise, many of the features that characterize (or distinguish) the various modern variants can be attributed to the original settler dialects as well as local native languages and dialects. Some organizations, such as SIL International, consider these approximately 30 different varieties to be separate languages, while others, such as the Library of Congress, consider them all to be dialects of Arabic.

In terms of sociolinguistics, a major distinction exists between the formal standardized language, found mostly in writing or in prepared speech, and the widely diverging vernaculars, used for everyday speaking situations. The latter vary from country to country, from speaker to speaker (according to personal preferences, education and culture), and depending on the topic and situation. In other words, Arabic in its natural environment usually occurs in a situation of diglossia, which means that its native speakers often learn and use two linguistic forms substantially different from each other, the Modern Standard Arabic (MSA) as the official language and a local colloquial variety (called العامية, al-ʿāmmiyya in many Arab countries, meaning "slang" or "colloquial"; or called الدارجة, ad-dārija, meaning "common or everyday language" in the Maghreb), in different aspects of their lives.

In sociolinguistics, a variety, also known as a lect or an isolect, is a specific form of a language or language cluster. This may include languages, dialects, registers, styles, or other forms of language, as well as a standard variety. The use of the word variety to refer to the different forms avoids the use of the term language, which many people associate only with the standard language, and the term dialect, which is often associated with non-standard language forms thought of as less prestigious or "proper" than the standard. Linguists speak of both standard and non-standard (vernacular) varieties as equally complex, valid, and full-fledged forms of language. Lect avoids the problem in ambiguous cases of deciding whether two varieties are distinct languages or dialects of a single language.

Variation at the level of the lexicon, such as slang and argot, is often considered in relation to particular styles or levels of formality (also called registers), but such uses are sometimes discussed as varieties as well.

In sociolinguistics, a register is a variety of language used for a particular purpose or particular communicative situation. For example, when speaking officially or in a public setting, an English speaker may be more likely to follow prescriptive norms for formal usage than in a casual setting, for example, by pronouncing words ending in -ing with a velar nasal instead of an alveolar nasal (e.g., walking rather than walkin), choosing words that are considered more formal, such as father vs. dad or child vs. kid, and refraining from using words considered nonstandard, such as ain't and y'all.

As with other types of language variation, there tends to be a spectrum of registers rather than a discrete set of obviously distinct varieties—numerous registers can be identified, with no clear boundaries between them. Discourse categorization is a complex problem, and even according to the general definition of language variation defined by use rather than user, there are cases where other kinds of language variation, such as regional or age dialect, overlap. Due to this complexity, scholarly consensus has not been reached for the definitions of terms such as register, field, or tenor; different scholars' definitions of these terms often contradict each other.

A speech community is a group of people who share a set of linguistic norms and expectations regarding the use of language. The concept is mostly associated with sociolinguistics and anthropological linguistics.

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:

In sociolinguistics, a sociolect is a form of language (non-standard dialect, restricted register) or a set of lexical items used by a socioeconomic class, profession, age group, or other social group.

Sociolects involve both passive acquisition of particular communicative practices through association with a local community, as well as active learning and choice among speech or writing forms to demonstrate identification with particular groups. The term sociolect might refer to socially restricted dialects, but it is sometimes also treated as equivalent with the concept of register, or used as a synonym for jargon and slang.