Allography

Allography, from the Greek for "other writing", has two meanings: a term in law for third party authorship; and a term in graphemics for alternative shapes for the same letter.

Authorship

An allograph may be the opposite of an autograph – i.e. a person's words or name (signature) written by someone else.^[1] In law, an allograph is a document not written by any of the parties involved.^[2]

Script

Historical allographs of Latin letters

a   U+0061 small "A" rendered with a top hook in most fonts	ɑ U+0251 small Latin alpha never has a top hook
ɡ   U+0261 small script "G" never has a looptail	g   U+0067 small "G" rendered with a looptail in some fonts
s U+0073 small "S"	ſ U+017F small long "S"

In graphemics, the term allograph denotes any glyphs that are considered variants of a letter or other grapheme, like a number or punctuation. An obvious example in English (and many other writing systems) is the distinction between uppercase and lowercase letters. Allographs can vary greatly, without affecting the underlying identity of the grapheme. Even if the word "cat" is rendered as "cAt", it remains recognizable as the sequence of the three graphemes ‹c›, ‹a›, ‹t›.^[3] Thus, if a group of individual glyphs (shapes that may or may not represent the same letter) are allographs (they do represent the same letter), they all represent a single grapheme (a single instance of the smallest unit of writing).

Letters and other graphemes can also have huge variations that may be missed by many readers. The letter g, for example, has two common forms (glyphs) in different typefaces, and an enormous variety in people's handwriting. A positional example of allography is the long s, a symbol which was once a widely used as a non-final allograph of the lowercase letter s. A grapheme variant can acquire a separate meaning in a specialized writing system. Several such variants have distinct code points in Unicode and so ceased to be allographs for some applications.^[4]

The concept of the allograph may be compared and contrasted with that of the homoglyph – glyphs of different meaning that are visually similar. For example, the letter O and the figure 0 have similar shape but have different meanings; the three letters A, Α and А look identical but are characters from three different scripts (Latin, Greek and Cyrillic).

Han characters

Main article: Variant Chinese characters

In the Han script, there exist several graphemes that have more than one written representation. Han typefaces often contain many variants of some graphemes. Different regional standards have adopted certain character variants. For instance:

Standard	Allograph	Definition
Mainland China	户	户
Japan	戸	戸
Taiwan	戶	戶

Typography

Official dimensions of the euro sign

Allographs of the sign in a selection of type faces

The term 'allograph' is used to describe the different representations of the same grapheme or character in different typefaces.^[5] The resulting font elements may look quite different in shape and style from the reference character or each other, but nevertheless their meaning remains the same.^[6] In Unicode, a given character is allocated a code point: all allographs of that character have the same code point and thus the essential meaning is retained irrespective of font choice at time of printing or display. Typically, for example, U+0067 g LATIN SMALL LETTER G is given a loop tail in serif typefaces but not in sans-serif faces (e.g., Times New Roman: g, Helvetica: g) but its code point is constant and its meaning persists irrespective of typeface. (The code U+0261 ɡ LATIN SMALL LETTER SCRIPT G is reserved for use with the International Phonetic Alphabet.)

See also

• Glyph – Element of writing
• Phonics – Method of teaching reading and writing of an alphabetic language
• Allophone – Phone used to pronounce a single phoneme

References

1. Jeremy Hawthorn (2000), A Glossary of Contemporary Literary Theory, Oxford University Press, ISBN 0-340-76195-4
2. "Allograph". The Law Dictionary. Retrieved 17 October 2023.
3. The Cambridge Encyclopedia of Language, second edition, Cambridge University Press, 1997, p. 196
4. Kumar, Sanjeev (2012-10-15). "A Comparative Study of UTF-8, UTF-16, and UTF-32 of Unicode Code Point". The IUP Journal of Telecommunications. Rochester, NY. IV (2): 50–59. SSRN 2161812.
5. Thomas Milo (2012). "Arabic Script Tutorial". nuqta.com. Retrieved 24 November 2019. In Arabic the abstract, nominal graphemes are represented by context-dependent allographs. Simplified support for Arabic handles contextual allographs according to two patterns, discontinuous and continuous assimilation. (Allographs and Ligatures)
6. David Rothlein; Brenda Rapp (3 April 2017). "The role of allograph representations in font-invariant letter identification". Journal of Experimental Psychology: Human Perception and Performance. 43 (7): 1411–1429. doi:10.1037/xhp0000384. PMC 5481478. PMID 28368166.