Iteration mark

thumb|upright=0.5|alt=A crop of a rubbing of a bronze bowl shows Chinese characters including a mark to indicate duplication of the preceding character.|Bronzeware script,

Iteration marks are characters or punctuation marks that represent a duplicated character or word.

Chinese

In Chinese, a smaller version of the character <span lang="zh" dir="ltr">二</span> (meaning "two"), as 𖿣 (), is used in casual writing to represent a doubled character, alongside and 々. However, it is not used in formal writing anymore, and it rarely appeared in printed matter. In a tabulated table or list, vertical repetition can be represented by a ditto mark ().

History

Iteration marks have been occasionally used for more than two thousand years in China. The example image shows an inscription in bronze script, a variety of formal writing dating to the Zhou dynasty, that ends with "<span lang="zh" dir="ltr">子<sub>二</sub>孫<sub>二</sub>寶用</span>", where <span lang="zh" dir="ltr"><sub>二</sub></span> is used as iteration marks in the phrase ("descendants to use and to treasure").

Malayo-Polynesian languages

In Filipino, Indonesian, and Malay, words that are repeated can be shortened with the use of numeral "2". For example, the Malay ("words", from single ) can be shortened to , and ("to walk around", from single ) can be shortened to . The usage of "2" can be also replaced with superscript "" (e.g. for ). The sign may also be used for reduplicated compound words with slight sound changes, for example for ("commotion"). Suffixes may be added after "2", for example in the word ("Western in nature", from the basic word ("West") with the prefix and suffix ).

The use of this mark dates back to the time when these languages were written with Arabic script, specifically the Jawi or Pegon varieties. Using the Arabic numeral , words such as (, butterfly) can be shortened to . The use of Arabic numeral was also adapted to several Brahmi derived scripts of the Malay archipelago, notably Javanese, Sundanese, Lontara, and Makassaran. As the Latin alphabet was introduced to the region, the Western-style Arabic numeral "2" came to be use for Latin-based orthography.

The use of "2" as an iteration mark was official in Indonesia up to 1972, as part of the Republican Spelling System. Its usage was discouraged when the Enhanced Indonesian Spelling System was adopted, and even though it is commonly found in handwriting, old signage or text messages, it is considered to be inappropriate for formal writing and documents.

Although Japanese kanji iteration marks are borrowed from Chinese, the grammatical function of duplication differs, as do the conventions on the use of these characters.

While Japanese does not have a grammatical plural form per se, some kanji can be reduplicated to indicate plurality (as a collective noun, not many individuals). This differs from Chinese, which normally repeats characters only for the purposes of adding emphasis, although there are some exceptions (e.g., , , "person"; , , "everybody").

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However, for some words duplication may alter the meaning:

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Using instead of repeating kanji is usually the preferred form, with two restrictions:

the reading must be the same, possibly with sound change (as above), and
the repetition must be within a single word.

When the reading is different, the second kanji is often simply written out to avoid confusion. Examples of such include:

The repetition mark is not used in every case where two identical characters appear side by side, but only where the repetition itself is etymologically significant—when the repetition is part of a single word. Where a character ends up appearing twice as part of a compound, it is usually written out in full:

, from + ("democracy" + "principle"); the abbreviated is only occasionally seen. One notable exception is in signs for – the name of neighborhoods often end in , which is then suffixed with yielding , which is then informally abbreviated to , despite the word break.

Similarly, in certain Chinese borrowings, it is generally preferred to write out both characters, as in ( Chinese multiplication table) or ( dan dan noodles), though in practice is often used.

In vertical writing, the character (Unicode U+303B), a cursive derivative of ("two", as in Chinese, above), can be employed instead, although this is increasingly rare.

Kana

Kana uses different iteration marks; one for hiragana, , and one for katakana, . The hiragana iteration mark is seen in some personal names like or , and it forms part of the formal name of the car company .

Unlike the kanji iteration marks, which do not reflect sound changes, kana iteration marks closely reflect sound, and the kana iteration marks can be combined with the voicing mark to indicate that the repeated syllable should be voiced, for example . If the first syllable is already voiced, for example , the voiced repetition mark still needs to be used: rather than , which would be read as .

While widespread in old Japanese texts, the kana iteration marks are generally not used in modern Japanese outside proper names, though they may appear in informal handwritten texts.

Repeating multiple characters

thumb|right|A variety of iteration marks in use in the classical text (73rd passage)

In addition to the single-character iteration marks, there are also two-character-sized repeat marks, which are used to repeat the preceding word or phrase. They are used in vertical writing only, and they are effectively obsolete in modern Japanese. The vertical kana repeat marks (unvoiced) and (voiced) resemble the hiragana character , giving them their name, . They stretch to fill the space typically occupied by two characters, but may indicate a repetition of more than two characters. For example, the duplicated phrase may be repeated as . If a (voiced mark) is added, it applies to the first sound of the repeated word; this is written as . For example, could be written horizontally as ; the voiced iteration mark only applies to the first sound .

In addition to the single-character representations and , Unicode provides the half-character versions , and , which can be stacked to render both voiced and unvoiced repeat marks:

{| lang="ja" style="padding-left: 3em"

| <div style='border:0;padding:0;font-size:15px;'><div style='height:1em;'>〳</div><div style='height:1em;'>〵</div></div> || <div style='border:0;padding:0;font-size:15px;'><div style='height:1em;'>〴</div><div style='height:1em;'>〵</div></div>

As support for these is limited, the ordinary forward slash and backward slash are occasionally used as substitutes.

Alternatively, multiple single-character iteration marks can be used, as in or . This practice is also uncommon in modern writing, though it is occasionally seen in horizontal writing as a substitute for the vertical repeat mark.

Unlike the single-kana iteration mark, if the first kana is voiced, the unvoiced version alone will repeat the voiced sound.

Further, if are present, then no iteration mark should be used, as in . This is prescribed by the Japanese Ministry of Education in its 1981 Cabinet notification prescribes, rule #6.

Nuosu

In the Nuosu language, is used to represent a doubled sound, for example , . It is used in all forms of writing.

Tangut

In Tangut manuscripts the sign is sometimes used to represent a doubled character; this sign does not occur in printed texts. In Unicode this character is , in the Ideographic Symbols and Punctuation block.

Egyptian hieroglyphs

In Egyptian hieroglyphs, the signs: <hiero>zp:Z1*Z1</hiero>   —   , literally meaning "two times", repeat the previous sign or word.

Khmer, Thai and Lao

Khmer (), Thai (), and Lao () each represent a repeated syllable where as it besides the word. This used to be written as numeral two () and the form changed over time. A repeated word could be used either to demonstrate plurality, to emphasize, or to soften the meaning of the original word.

Ditto mark

In English, Spanish, French, Italian, German, Portuguese, Czech, Polish and Turkish lists, the ditto mark (″) represents a word repeated from the equivalent position in the line above it; or an evenly-spaced row of ditto marks represents any number of words repeated from above. For example:

<pre>

Two pounds of lettuce

Three " " tomatoes

Four " " onions

One " " carrots

</pre>

This is common in handwriting and formerly in typewritten texts.

In Unicode, the ditto mark of Western languages has been defined to be equivalent to the . The separate character is to be used in the CJK scripts only.

The convention in Polish handwriting, Czech, Swedish, and Austrian German is to use a ditto mark on the baseline together with horizontal lines spanning the extent of the word repeated, for example:

Superscript numeral

In western mathematics, the superscript numeral originated as a notation for exponentiation. Over time, its meaning expanded to represent repeated function application as well, effectively making it a notation for marking iteration. This sense was eventually borrowed in non mathematical text to represent repeated symbols, especially to mark repeated letters in acronyms. The superscript is occasionally left out, either colloquially or in the formal representation of the acronym, due to either typographic or stylistic concerns. Notable examples include the bus protocol I<sup>2</sup>C, the World Wide Web Consortium (W3C), and the fan-fiction hosting website AO3.