Metalanguage

Metalanguage in linguistics is a language used to make statements about language (the object language). Formal syntactic models for the description of grammar, e.g. generative grammar, are a type of metalanguage. More broadly, it can refer to any terminology or language used to discuss language itself - a written grammar, for example, or a discussion about language use.

For example, common linguistic statements can be rendered in the form of logic statements, e.g. John smokes can be written as S(j), where S=smokes and j=john.

Kinds
There are a variety of recognized kinds of metalanguages including embedded, ordered, and nested or hierarchical.

Embedded metalanguages, as their name suggests, are metalanguages embedded in an object language. They occur both formally and naturally. This idea is found in Douglas Hofstadter's book Gödel, Escher, Bach in his discussion of the relationship between formal languages and number theory: "...it is in the nature of any formalization of number theory that its metalanguage is embedded within it" (pg.270). They occur in informal languages as well, such as in English, where adjectives, adverbs, and possessive pronouns serve as an embedded metalanguage, while nouns, verbs, and in some instances adjectives and adverbs serve as an object language. Thus the term 'red' in the phrase 'red barn' is part of the embedded metalanguage of English and the term 'barn' is part of the object language. A similar example for adverbs is the term 'slowly' in the phrase 'slowly running'.

Ordered metalanguages are analogous to ordered logics. An example of an ordered metalanguage would be the construction of one metalanguage to talk about an object language, then creating another metalanguage to talk about the first metalanguage, and so on for as long as is necessary.

Nested or hierarchical metalanguages are similar to ordered metalanguages in that each level represents a greater degree of abstraction. However, nested metalanguages differ from ordered ones in that each level includes the one below. The paradigmatic example of a nested metalanguage comes from the Linnean taxonomic system in biology. Each level in the system incorporates the one below it. The language used to talk about genus is also used to talk about species, the language that is used to talk about orders is also used to talk about geni, and so on up to kingdoms.

Role in metaphor
Michael Reddy (1979) has demonstrated that much of the language we use to talk about language is conceptualized and structured by what he refers to as the conduit metaphor. The conduit metaphor is actually three interconnected metaphors: Reddy offers sentences similar to the following as evidence:
 * Concepts, thoughts, feelings, meanings, sense and ideas are objects.
 * Words, sentences, and so on are containers (with an inside and an outside) for these objects.
 * Finally, communication is the act of sending and receiving these containers (through a conduit).


 * 1) What is the meaning in his words?
 * 2) Try to get your thoughts into words.
 * 3) I couldn't get any meaning out of his words.
 * 4) I couldn't find any sense in his words.
 * 5) His words were empty and 'devoid' of feeling.
 * 6) His promises were hollow.
 * 7) His ideas were hidden in a dense thicket of sentences.
 * 8) Like a maggot in a turd he hid within the word.
 * 9) How do I convey my love in mere words.
 * 10) How do I get it across to you that I don't want to see you again.
 * 11) I gave her a call.
 * 12) I received your call.
 * 13) I got the message.

Reddy estimates that fully 70% of the language we use to talk about the English language is based on this metaphor. While recognizing the prominence of this metaphor, Reddy is deeply troubled by it. He thinks of it as erroneous, misleading, and dehumanizing.

Computing
HTML and XHTML are examples of markup languages that can be used by anyone wishing to translate media including video, sound, graphics and text into a language intelligible to a computer and suitable for display on the Internet. Originally this required manually typing up an HTML document but there are software programs that will do this now. There are in addition special mark up languages for mathematical and scientific notation such as Tex and LaTeX or one of its many variants.

Another common example of a metalanguage in computing is XML. Many other metalanguages have been based on the W3C XML 1.0 standard, including
 * XQuery (An XML based Query language)
 * XLink
 * SVG
 * SMIL
 * Many More