Letter case
Most western languages (certainly those based on Latin, Cyrillic, and Greek alphabets) use multiple letter cases in their written form as an aid to clarity. In addition, some computer programming languages use letter case to distinguish between special words, while others ignore case altogether.
In English, upper case letters (aka capital letters, or majuscules) are used as the first letter of a sentence or a proper noun and for initials or acronyms. Lower case letters (aka minuscules) are normally used for all other purposes. There are however situations where further capitalisation may be used to give added emphasis, for example in headings and titles or to PICK OUT certain words. Other languages vary in their use of capitals. For example, in German you additionally capitalise the first letter of all nouns.
The terms upper and lower case come from the days of mechanical printing presses that used lead type, where the capital letters were kept in the upper tray, while the small letters were kept in the lower one.
See also: Sentence case
To be merged
In orthography and typography, case is the distinction between majuscule (capital, uppercase) and minuscule (lowercase) letters. Only alphabetic writing systems have case, but not all of them. Examples are the modern Greek, Latin, Cyrillic, and Armenian alphabets.
If an alphabet has case, all or nearly all letters have both a majuscule and minuscule form. Both forms in each pair are considered to be the same letter: they have the same name, same pronunciation, and will be treated identically when sorting in alphabetical order. Languages have capitalisation rules to determine whether majuscules or minuscules are to be used in a given context.
An example of a letter without both forms is the German ß (ess-tsett), which exists only in minuscule. When capitalized it becomes two letters, "SS" (although use of ß as a capital has been deemed permissible according to the recent spelling reform). This is because ß was originally a ligature of the two letters "ſs", both of which become "S" when capitalized. It evolved into a letter in its own right. (ß is also occasionally referred to as a ligature of "sz", which recalls the way this consonant was pronounced in some medieval German dialects. The original spelling "sz" is preserved in Hungarian, which is pronounced as [s].)
The distinction between hiragana and katakana in Japanese is similar to, but not the same as, case. While each sound has both a hiragana and katakana,
any given word will use only one of the two scripts normally. If a word is written with hiragana, it is not normally considered correct to write it with katakana, and vice versa. However, katakana may be substituted for hiragana or kanji to add emphasis or make them stand out, similar to the use of capitalization or italics in English.
The term case derives from early printers' jargon. The individual type blocks used in hand typesetting are stored in wooden or metal cases, sorted by letter. For an alphabet that uses majuscules and minuscules, typesetters need two cases at hand, one for each form. Historically, these were placed one above another on a rack on the typesetter's desk. The upper case contained majuscules, the lower case had the minuscules.
