Contents introduction chapter I. Bases of english language and its stylistic layers

1.2. Difference between formal scientific language and slang.
Formal scientific language.
In mathematics, computer science, and linguistics, a formal language is a set of strings of symbols together with a set of rules that are specific to it.
The alphabet of a formal language is the set of symbols, letters, or tokens from which the strings of the language may be formed; frequently it is required to be finite. The strings formed from this alphabet are called words, and the words that belong to a particular formal language are sometimes called well-formed words or well-formed formulas. A formal language is often defined by means of a formal grammar such as a regular grammar or context-free grammar, also called its formation rule [17, 85-86].
The field of formal language theory studies primarily the purely syntactical aspects of such languages-that is, their internal structural patterns. Formal language theory sprang out of linguistics, as a way of understanding the syntactic regularities of natural languages. In computer science, formal languages are used among others as the basis for defining the grammar of programming languages and formalized versions of subsets of natural languages in which the words of the language represent concepts that are associated with particular meanings or semantics.
In computational complexity theory, decision problems are typically defined as formal languages, and complexity classes are defined as the sets of the formal languages that can be parsed by machines with limited computational power. In logic and the foundations of mathematics, formal languages are used to represent the syntax of axiomatic systems, and mathematical formalism is the philosophy that all of mathematics can be reduced to the syntactic manipulation of formal languages in this way.
A formal language L over an alphabet Σ is a subset of Σ*, that is, a set of words over that alphabet. Sometimes the sets of words are grouped into expressions, whereas rules and constraints may be formulated for the creation of 'well-formed expressions’.
In computer science and mathematics, which do not usually deal with natural languages, the adjective “formal” is often omitted as redundant.
The study of interpretations of formal languages is called formal semantics. In mathematical logic, this is often done in terms of model theory. In model theory, the terms that occur in a formula are interpreted as objects within mathematical structures, and fixed compositional interpretation rules determine how the truth value of the formula can be derived from the interpretation of its terms; a model for a formula is an interpretation of terms such that the formula becomes true.
Linguistics and the philosophy of language, a natural language or ordinary language is any language that has evolved naturally in humans through use and repetition without conscious planning or premeditation. Natural languages can take different forms, such as speech, signing, or writing. They are distinguished from constructed and formal languages such as those used to program computers or to study logics.
Defining natural language.
Though the exact definition varies between scholars, natural language can broadly be defined in contrast to artificial or constructed languages (such as computer programming languages and international auxiliary languages) and to other communication systems in nature. Such examples include bees’ waggle dance and whale song, to which researchers have found and/or applied the linguistic cognates of dialect and even syntax.
An unstandardized language such as African American Vernacular English, for example, is a natural language, whereas a standardized language such as Standard American English is, in part, prescribed.
Controlled languages.
Controlled natural languages are subsets of natural languages whose grammars and dictionaries have been restricted in order to reduce or eliminate both ambiguity and complexity (for instance, by cutting down on rarely used superlative or adverbial forms or irregular verbs). The purpose behind the development and implementation of a controlled natural language typically is to aid non-native speakers of a natural language in understanding it, or to ease computer processing of a natural language. An example of a widely used controlled natural language is Simplified English, which was originally developed for aerospace industry maintenance manuals.
Defining slang.
Slang consists of a lexicon of non-standard words and phrases in a given language. Use of these words and phrases is typically associated with the subversion of a standard variety (such as Standard English) and is likely to be interpreted by listeners as implying particular attitudes on the part of the speaker. In some contexts, a speaker’s selection of slang words or phrases may convey prestige, indicating group membership or distinguishing group members from those who are not a part of the group.
Interpretations and models.
Formal languages are entirely syntactic in nature but may be given semantics that give meaning to the elements of the language. For instance, in mathematical logic, the set of possible formulas of a particular logic is a formal language, and an interpretation assigns a meaning to each of the formulas - usually, a truth value.
Michael Adams remarks that, “Slang is liminal language... it is often impossible to tell, even in context, which interests and motives it serves... slang is on the edge. Slang dictionaries, collecting thousands of slang entries, offer a broad, empirical window into the motivating forces behind slang”.
Although jargon and slang can both be used to exclude non-group members from the conversation, the intention of jargon is to optimize conversation using terms that imply technical understanding. On the other hand, slang tends to emphasize social and contextual understanding.
While colloquialisms and jargon may seem like slang because they reference a particular group, they do not fit the same definition, because they do not represent a particular effort to replace standard language. Colloquialisms are considered more standard than slang, and jargon is often created to talk about aspects of a particular field that are not accounted for in the standard lexicon.
It is often difficult to differentiate slang from colloquialisms and even more standard language, because slang generally becomes accepted into the standard lexicon over time. Words such as “spurious” and “strenuous” were once slang, though they are now accepted as standard, even high register words. The literature on slang even discusses mainstream acknowledgment of a slang term as changing its status as true slang, because it has been accepted by the media and is thus no longer the special insider speech of a particular group.
Nevertheless, a general test for whether a word is a slang word or not is whether it would be acceptable in an academic or legal setting, as both are arenas in which standard language is considered necessary and/or whether the term has been entered in the Oxford English Dictionary, which some scholars claim changes its status as slang.
Formation of slang. It is often difficult to collect etymologies for slang terms, largely because slang is a phenomenon of speech, rather than written language and etymologies which are typically traced via corpus.
Eric Partridge, cited as the first to report on the phenomenon of slang in a systematic and linguistic way, postulated that a term would likely be in circulation for a decade before it would be written down. Nevertheless, it seems that slang generally forms via deviation from a standard form. This “spawning” of slang occurs in much the same way that any general semantic change might occur. The difference here is that the slang term's new meaning takes on a specific social significance having to do with the group the term indexes. Coleman also suggests that slang is differentiated within more general semantic change in that it typically has to do with a certain degree of “playfulness”. The development of slang is considered to be a largely “spontaneous, lively, and creative” speech process.
Still, while a great deal of slang takes off, even becoming accepted into the standard lexicon, much slang dies out, sometimes only referencing a group. An example of this is the term “groovy” which is a relic of 1960’s and 70’s American “hippy” slang. Nevertheless, for a slang term to become a slang term, people must use it, at some point in time, as a way to flout standard language.
Additionally, slang terms may be borrowed between groups, such as the term “gig” which was originally coined by jazz musicians in the 1930s and then borrowed into the same hippy slang of the 1960s. The word “groovy” has remained a part of subculture lexicon since its popularization. It is still in common use today by a significant population. The word “gig” to refer to a performance very likely originated well before the 1930s, and remained a common term throughout the 1940s and 1950s before becoming a vaguely associated with the “hippy slang of the 1960s”. The word “gig” is now a widely accepted synonym for a concert, recital, or performance of any type. “Hippy” is more commonly spelled “hippie”.
Generally, slang terms undergo the same processes of semantic change that words in the regular lexicon do [5, 15-19].