Unicode Explained

Character Requirements of Languages

Although Unicode contains almost all characters used in currently used languages, it

is still and will always be relevant to consider the character requirements that different

languages impose. Here we will first list some of the reasons for this, and then analyze

the concept of “character requirements,” and finally study some specific languages.

The Impact of Character Repertoire

As mentioned in the section “Definitions of Character Repertoires” in Chapter 1, there

are good reasons to try to estimate the repertoire of characters that will appear in a

document or in an application. In more detail, the reasons include the following:

• A font typically supports a limited character repertoire only. Full Unicode fonts

are rare, and usually not suitable for copy text.

• In particular, artistic or otherwise special fonts, such as those used for headings

and buttons, often have a very limited character repertoire.

• A program that will be used for processing your document in some way might be

prepared to handle a limited repertoire only.

• Special characters in normal text often result from mistyping or other errors. When

checking input data, it is often useful to detect any “unusual” characters and issue

warnings about them.

• In particular, character recognition (in scanning text or in processing handwritten

characters) works best if the assumed repertoire is small. ...