Character sets can differ in the number of alphabetic characters and special characters. While the English alphabet contains only 26 characters, some languages contain many more characters. Japanese, for example, can contain over 20,000 characters and Chinese can contain an even higher number of characters.
The alphabets of most western European countries are similar to the standard 26-character alphabet used in English-speaking countries. These alphabets often also include some additional basic characters, some marked or accented characters, and some ligatures.
Although each character in Hiragana has an equivalent in Katakana, Hiragana is the most common script, with cursive rather than block-like letter forms. Kanji characters are used to write root words. Katakana is mostly used to represent “foreign” words, that is, words imported from languages other than Japanese.
Kanji has tens of thousands of characters, but the number commonly used has declined steadily over the years. Now only about 3500 are frequently used, although the average Japanese writer has a vocabulary of about 2000 Kanji characters. Nonetheless, computer systems must support more than 7000 characters in accordance with the Japan Industry Standard (JIS) requirements. In addition, there are about 170 Hiragana and Katakana characters. On average, 55% of Japanese text is Hiragana, 35% Kanji, and 10% Katakana. Arabic numerals and Roman letters are also present in Japanese text.
Although completely avoiding the use of Kanji is possible, most Japanese readers find a text that is composed without any Kanji hard to understand.
Korean text can be written using a phonetic writing system called Hangul. Hangul has more than 11,000 characters, which consist of consonants and vowels known as jamos. About 3000 characters from the entire Hangul vocabulary of characters are usually used in Korean computer systems. Korean also uses ideographs based on the set invented in China, called Hanja. Korean text requires over 6000 Hanja characters. Hanja is used mostly to avoid confusion when Hangul would be ambiguous. Hangul characters are formed by combining consonants and vowels. After these characters are combined, they can compose one syllable, which is a Hangul character. Hangul characters are often arranged in a square, so that the group takes up the same space as a Hanja character. Arabic numerals, Roman letters, and special symbol characters are also present in Korean text.
A Thai character can be defined as a column position on a display screen with four display cells. Each column position can have up to three characters. The composition of a display cell is based on the Thai character's classification. Some Thai characters can be composed with another character's classification. If both characters can be composed together, both characters are in the same cell. Otherwise, they are in separate cells.
In the People's Republic of China (PRC) there are about 7000 commonly used Hanzi characters in the GB2312 (zh locale), more than 20,000 characters in the GBK charset (zh.GBK locale), and about 30,000 characters in the GB18030-2000 charset (zh_CN.GB18030 locale), including all CJK extension A characters defined in Unicode 3.0.
If a character is not a root character, it usually consists of two or more parts, two being most common. In two-part characters, one part generally represents meaning, and the other represents pronunciation. Occasionally both parts represent meaning. The radical is the most important element, and characters are traditionally arranged by radical, of which there are several hundred. A single sound can be represented by many different characters, which are not interchangeable in usage. A single character can have different sounds.
Some characters are more appropriate than others in a given context. The appropriate character is distinguished phonetically by the use of tones. By contrast, spoken Japanese and Korean lack tones.
Several phonetic systems represent Chinese. In the People's Republic of China the most common is pinyin, which uses Roman characters and is widely employed in the West for place names such as Beijing. The Wade-Giles system is an older phonetic system, formerly used for place names such as Peking. In Taiwan zhuyin (or bopomofo), a phonetic alphabet with unique letter forms, is often used instead.
Hebrew text is used for writing scripts in the Hebrew and Yiddish languages. Hebrew uses a bidirectional script. Hebrew letters are written and read from right to left, while numbers are read from left to right. Any English text that is embedded in Hebrew text is also read from left to right.
Hebrew uses a 27-character alphabet, and takes punctuation marks and numbers from the standard Latin (or English) alphabet. Hebrew text also includes vowel and pronunciation marks. These marks appear either as a dot (dagesh) inside the base character, vowel marks below the character, or accents to the upper left of the character. These marks are generally only used in liturgical text, and are rarely seen in day-to-day use. Hebrew has no uppercase letters.
Hindi text is written in a script called Devanagari, which means the writing of the gods. Hindi is a phonetic language, and is written as a series of syllables. Each syllable is built up of alphabetic pieces (the Devanagari characters) of three types: consonant letters, independent vowels, and dependent vowel signs. The syllable itself consists of a consonant and vowel core, with an optional preceding consonant. Unlike English, which starts from a baseline, Devanagari characters hang from a horizontal line (called the head stroke) written at the top of the characters. These characters can combine or change shape depending on their context. Like Hebrew, Hindi text makes no distinction between uppercase and lowercase letters.