Logogram

In a written language, a logogram, also logograph or lexigraph, is a written character that represents a semantic component of a language, such as a word or morpheme. Chinese characters as used in Chinese as well as other languages are logograms, as are Egyptian hieroglyphs and characters in cuneiform script. A writing system that primarily uses logograms is called a logography. Non-logographic writing systems, such as alphabets and syllabaries, are phonemic: their individual symbols represent sounds directly and lack any inherent meaning. However, all known logographies have some phonetic component, generally based on the rebus principle, and the addition of a phonetic component to pure ideographs is considered to be a key innovation in enabling the writing system to adequately encode human language.

Types of logographic systems

Some of the earliest recorded writing systems are logographic; the first historical civilizations of Mesopotamia, Egypt, China and Mesoamerica all used some form of logographic writing.
All logographic scripts ever used for natural languages rely on the rebus principle to extend a relatively limited set of logograms: A subset of characters is used for their phonetic values, either consonantal or syllabic. The term logosyllabary is used to emphasize the partially phonetic nature of these scripts when the phonetic domain is the syllable. In Ancient Egyptian hieroglyphs, Ch'olti', and in Chinese, there has been the additional development of determinatives, which are combined with logograms to narrow down their possible meaning. In Chinese, they are fused with logographic elements used phonetically; such "radical and phonetic" characters make up the bulk of the script. Ancient Egyptian and Chinese relegated the active use of rebus to the spelling of foreign and dialectical words.

Logoconsonantal

Logoconsonantal scripts have graphemes that may be extended phonetically according to the consonants of the words they represent, ignoring the vowels. For example, Egyptian G38 was used to write both sȝ 'duck' and sȝ 'son', though it is likely that these words were not pronounced the same except for their consonants. The primary examples of logoconsonantal scripts are Egyptian hieroglyphs, hieratic, and demotic: Ancient Egyptian.

Logosyllabic

Logosyllabic scripts have graphemes which represent morphemes, often polysyllabic morphemes, but when extended phonetically represent single syllables. They include cuneiform, Anatolian hieroglyphs, Cretan hieroglyphs, Linear A and Linear B, Chinese characters, Maya script, Aztec script, Mixtec script, and the first five phases of the Bamum script.

Others

A peculiar system of logograms developed within the Pahlavi scripts used to write Middle Persian during much of the Sassanid period; the logograms were composed of letters that spelled out the word in Aramaic but were pronounced as in Persian. These logograms, called Frahang-i Pahlavig, were dispensed with altogether after the Arab conquest of Persia and the adoption of a variant of the Arabic alphabet.

Semantic and phonetic dimensions

All historical logographic systems include a phonetic dimension, as it is impractical to have a separate basic character for every word or morpheme in a language. In some cases, such as cuneiform as it was used for Akkadian, the vast majority of glyphs are used for their sound values rather than logographically. Many logographic systems also have a semantic/ideographic component, called "determinatives" in the case of Egyptian and "radicals" in the case of Chinese.
Typical Egyptian usage was to augment a logogram, which may potentially represent several words with different pronunciations, with a determinate to narrow down the meaning, and a phonetic component to specify the pronunciation. In the case of Chinese, the vast majority of characters are a fixed combination of a radical that indicates its nominal category, plus a phonetic to give an idea of the pronunciation. The Mayan system used logograms with phonetic complements like the Egyptian, while lacking ideographic components.

Universal logograms

Not all logograms are associated with one specific language, and some are not associated with any language at all. The ampersand is a logogram in the Latin script, a combination of the letters "e" and "t." In Latin, "et" translates to "and," and the ampersand is still used to represent this word today, however, it does so in a variety of languages, being a representative of morphemes "and," "y," or "en," if they are a speaker of English, Spanish, or Dutch, respectively.
Outside of any script is Unicode, a compilation of characters of various meanings. They state their intention to build the standard to include every character from every language. It's the generally accepted standard for computer character encoding, but others, like ASCII and Baudot, exist and serve various purposes in digital communication. Many logograms in these databases are ubiquitous, and are used on the Internet by users worldwide.

Chinese characters

Chinese scholars have traditionally classified Chinese characters into six types by etymology.
The first two types are "single-body", meaning that the character was created independently of other characters. "Single-body" pictograms and ideograms make up only a small proportion of Chinese logograms. More productive for the Chinese script were the two
"compound" methods, i.e. the character was created from assembling different characters. Despite being called "compounds", these logograms are still single characters, and are written to take up the same amount of space as any other logogram. The final two types are methods in the usage of characters rather than the formation of characters themselves.

The first type, and the type most often associated with Chinese writing, are pictograms, which are pictorial representations of the morpheme represented, e.g. 山 for 'mountain'.
The second type are the ideograms that attempt to visualize abstract concepts, such as 上 'up' and 下 'down'. Also considered ideograms are pictograms with an ideographic indicator; for instance, 刀 is a pictogram meaning 'knife', while 刃 is an ideogram meaning 'blade'.
Radical–radical compounds, in which each element of the character hints at the meaning. For example, 休 'rest' is composed of the characters for 'person' and 'tree', with the intended idea of someone leaning against a tree, i.e. resting.
Radical–phonetic compounds, in which one component indicates the general meaning of the character, and the other hints at the pronunciation. An example is 樑, where the phonetic 梁 liáng indicates the pronunciation of the character and the radical 木 indicates its meaning of 'supporting beam'. Characters of this type constitute around 90% of Chinese logograms.
Changed-annotation characters are characters which were originally the same character but have bifurcated through orthographic and often semantic drift. For instance, 樂 / 乐 can mean both 'music' and 'pleasure'.
Improvisational characters come into use when a native spoken word has no corresponding character, and hence another character with the same or a similar sound is "borrowed"; occasionally, the new meaning can supplant the old meaning. For example, 自 used to be a pictographic word meaning 'nose', but was borrowed to mean 'self', and is now used almost exclusively to mean the latter; the original meaning survives only in stock phrases and more archaic compounds. Because of their derivational process, the entire set of Japanese kana can be considered to be of this type of character, hence the name kana. Example: Japanese 仮名; 仮 is a simplified form of Chinese 假 used in Korea and Japan, and 假借 is the Chinese name for this type of characters.

The most productive method of Chinese writing, the radical-phonetic, was made possible by ignoring certain distinctions in the phonetic system of syllables. In Old Chinese, post-final ending consonants and were typically ignored; these developed into tones in Middle Chinese, which were likewise ignored when new characters were created. Also ignored were differences in aspiration ; the Old Chinese difference between type-A and type-B syllables ; and sometimes, voicing of initial obstruents and/or the presence of a medial after the initial consonant. In earlier times, greater phonetic freedom was generally allowed. During Middle Chinese times, newly created characters tended to match pronunciation exactly, other than the tone – often by using as the phonetic component a character that itself is a radical-phonetic compound.
Due to the long period of language evolution, such component "hints" within characters as provided by the radical-phonetic compounds are sometimes useless and may be misleading in modern usage. As an example, based on 每 'each', pronounced měi in Standard Mandarin, are the characters 侮 'to humiliate', 悔 'to regret', and 海 'sea', pronounced respectively wǔ, huǐ, and hǎi in Mandarin. Three of these characters were pronounced very similarly in Old Chinese – , , and according to a recent reconstruction by William H. Baxter and Laurent Sagart – but sound changes in the intervening 3,000 years or so have resulted in radically different pronunciations.

Chinese characters used in Japanese and Korean

Within the context of the Chinese language, Chinese characters by and large represent words and morphemes rather than pure ideas; however, the adoption of Chinese characters by the Japanese and Korean languages have resulted in some complications to this picture.
Many Chinese words, composed of Chinese morphemes, were borrowed into Japanese and Korean together with their character representations; in this case, the morphemes and characters were borrowed together. In other cases, however, characters were borrowed to represent native Japanese and Korean morphemes, on the basis of meaning alone. As a result, a single character can end up representing multiple morphemes of similar meaning but with different origins across several languages. Because of this, kanji and hanja are sometimes described as morphographic writing systems.