Tilde


The tilde is a grapheme or with a number of uses. The name of the character came into English from Spanish, which, in turn, came from the Latin, meaning 'title' or 'superscription'. Its primary use is as a diacritic in combination with a base letter. Its freestanding form is used in modern texts mainly to indicate approximation.

History

Use by medieval scribes

The tilde was originally one of a variety of marks written over an omitted letter or several letters as a scribal abbreviation. Thus, the commonly used words Anno Domini were frequently abbreviated to Ao Dñi, with an elevated terminal with a contraction mark placed over the "n", such a mark could denote the omission of one letter or several letters. This saved on the expense of the scribe's labor and the cost of vellum and ink. Medieval European charters written in Latin are largely made up of such abbreviated words with contraction marks and other abbreviations; only uncommon words were given in full.
The text of the Domesday Book of 1086, relating for example, to the manor of Molland in Devon, is highly abbreviated as indicated by numerous tildes.
The text with abbreviations expanded is as follows:

Role of mechanical typewriters

On typewriters designed for languages that routinely use diacritics, there are two possible solutions. Keys can be dedicated to precomposed characters or alternatively a dead key mechanism can be provided. With the latter, a mark is made when a dead key is typed, but unlike normal keys, the paper carriage does not move on and thus the next letter to be typed is printed under that accent. Typewriters for Spanish typically have a dedicated key for Ñ/ñ but, as Portuguese uses Ã/ã and Õ/õ, a single dead-key is the most practical solution.
The tilde symbol did not exist independently as a movable type or hot-lead printing character since the type cases for Spanish or Portuguese would include sorts for the accented forms.

The centralized ASCII tilde

The first ASCII standard did not have a tilde. Like Portuguese and Spanish, the French, German and Scandinavian languages also needed symbols in excess of the basic 26 needed for English. The ASA worked with and through the CCITT to internationalize the code-set, to meet the basic needs of at least the Western European languages.
Thus ISO646 was born, providing the tilde and other symbols as optional characters.
ISO646 and ASCII incorporated many of the overprinting lower-case diacritics from typewriters, including tilde. Overprinting was intended to work by putting a backspace code between the codes for letter and diacritic. However even at that time, mechanisms that could do this or any other overprinting were not widely available, did not work for capital letters, and were impossible on video displays, with the result that this concept failed to gain significant acceptance. Consequently, many of these free-standing diacritics were quickly reused by software as additional syntax, basically becoming new types of syntactic symbols that a programming language could use. As this usage became predominant, type design gradually evolved so these diacritic characters became larger and more vertically centered, making them useless as overprinted diacritics but much easier to read as free-standing characters that had come to be used for entirely different and novel purposes. Most modern fonts align the plain ASCII "spacing" tilde at the same level as dashes, or only slightly higher.
The free-standing tilde is at code 126 in ASCII, where it was inherited into Unicode as U+007E.
A similar shaped mark is known in typography and lexicography as a swung dash: these are used in dictionaries to indicate the omission of the entry word.

Connection to Spanish

As indicated by the etymological origin of the word "tilde" in English, this symbol has been closely associated with the Spanish language. The connection stems from the use of the tilde above the letter to form the letter in Spanish, a feature shared by only [|a few other languages], most of which are historically connected to Spanish. This peculiarity can help non-native speakers quickly identify a text as being written in Spanish with little chance of error. Particularly during the 1990s, Spanish-speaking intellectuals and news outlets demonstrated support for the language and the culture by defending this letter against globalisation and computerisation trends that threatened to remove it from keyboards and other standardised products and codes. The Instituto Cervantes, founded by Spain's government to promote the Spanish language internationally, chose as its logo a highly stylised with a large tilde. The 24-hour news channel CNN in the US later adopted a similar strategy on its existing logo for the launch of its Spanish-language version, therefore being written as CN͠N. And similarly to the National Basketball Association, the Spain men's national basketball team is nicknamed "ÑBA".
In Spanish itself the word tilde is used more generally for diacritics, including the stress-marking acute accent. The diacritic is more commonly called virgulilla or la tilde de la eñe, and is not considered an accent mark in Spanish, but rather simply a part of the letter .

Usage

Common use in English

The English language does not use the tilde as a diacritic, though it is used in some loanwords. The standalone form of the symbol is used more widely. Informally, it means "approximately", "about", or "around", such as "~30 minutes before", meaning "approximately 30 minutes before". It may also mean "similar to", including "of the same order of magnitude as", such as "" meaning that and are of the same order of magnitude. Another approximation symbol is the double tilde, meaning "approximately/almost equal to". The tilde is also used to indicate congruence of shapes by placing it over an symbol, thus.
In more recent digital usage, tildes on either side of a word or phrase have sometimes come to convey a particular tone that "let the enclosed words perform both sincerity and irony", which can pre-emptively defuse a negative reaction. For example, BuzzFeed journalist Joseph Bernstein interprets the tildes in the following tweet:
in the ~ spirit of the season ~ will now link to some of the #Bestof2014 sports reads. if you hate nice things, mute that hashtag.

as a way of making it clear that both the author and reader are aware that the enclosed phrase – "spirit of the season" – "is cliche and we know this quality is beneath our author, and we don't want you to think our author is a cliche person generally".
Among other uses, the symbol has been used on social media to indicate sarcasm. It may also be used online, especially in informal writing such as fanfiction, to convey a cutesy, playful, or flirtatious tone.

Diacritical use

In some languages, the tilde is a diacritic mark placed over a letter to indicate a change in its pronunciation:

Pitch

The tilde was firstly used in the polytonic orthography of Ancient Greek, as a variant of the circumflex, representing a rise in pitch followed by a return to standard pitch.

Abbreviation

Nasalization

It is also as a small that the tilde originated when written above other letters, marking a Latin which had been elided in old Galician-Portuguese. In modern Portuguese it indicates nasalization of the base vowel: mão "hand", from Lat. manu-; razões "reasons", from Lat. rationes. This usage has been adopted in the orthographies of several native languages of South America, such as Guarani and Nheengatu, as well as in the International Phonetic Alphabet and many other phonetic alphabets. For example, is the IPA transcription of the pronunciation of the French place-name Lyon.
In Breton, the symbol after a vowel means that the letter serves only to give the vowel a nasalised pronunciation, without being itself pronounced, as it normally is. For example, gives the pronunciation whereas gives.
In the DMG romanization of Tunisian Arabic, the tilde is used for nasal vowels õ and ṏ.

Palatal n

The tilded developed from the digraph in Spanish. In this language, is considered a separate letter called eñe, rather than a letter-diacritic combination; it is placed in Spanish dictionaries between the letters and. In Spanish, the word tilde actually refers to diacritics in general, e.g. the acute accent in José, while the diacritic in is called "virgulilla" or . Current languages in which the tilded is used for the palatal nasal consonant include
In Vietnamese, a tilde over a vowel represents a creaky rising tone. Letters with the tilde are not considered separate letters of the Vietnamese alphabet.

International Phonetic Alphabet

In phonetics, a tilde is used as a diacritic that is placed above a letter, below it or superimposed onto the middle of it:
  • A tilde above a letter indicates nasalization, e.g..
  • A tilde superimposed onto the middle of a letter indicates velarization or pharyngealization, e.g.. If no precomposed Unicode character exists, the Unicode character can be used to generate one.
  • A tilde below a letter indicates laryngealisation, e.g.. If no precomposed Unicode character exists, the Unicode character can be used to generate one.
A tilde between two phonemes indicates optionality, or "alternates with". E.g. could indicate that the sounds may alternate depending on context, or that they vary based on region or speaker, or some other variation.