It is the International Standards Organization (ISO) that defines the standard character-sets for different alphabets/languages.
The different character-sets being used around the world are listed below:
Because the character-sets listed above are limited in size, and are not compatible in multilingual environments, the Unicode Consortium developed the Unicode Standard.
The Unicode Standard covers all the characters, punctuations, and symbols in the world.
Unicode enables processing, storage and interchange of text data no matter what the platform, no matter what the program, no matter what the language.
The Unicode Consortium develops the Unicode Standard. Their goal is to replace the existing character-sets with its standard Unicode Transformation Format (UTF).
The Unicode Standard has become a success and is implemented in XML, Java, ECMAScript (JavaScript), LDAP, CORBA 3.0, WML, etc. The Unicode standard is also supported in many operating systems and all modern browsers.
The Unicode Consortium cooperates with the leading standards development organizations, like ISO, W3C, and ECMA.
Unicode can be implemented by different character-sets. The most commonly used encodings are UTF-8 and UTF-16:
Character-set
UTF-8
UTF-16
Description
A character in UTF8 can be from 1 to 4 bytes long. UTF-8 can represent any character in the Unicode standard. UTF-8 is backwards compatible with ASCII. UTF-8 is the preferred encoding for e-mail and web pages
16-bit Unicode Transformation Format is a variable-length character encoding for Unicode, capable of encoding the entire Unicode repertoire. UTF-16 is used in major operating systems and environments, like Microsoft Windows 2000/XP/2003/Vista/CE and the Java and .NET byte code environments
Tip: The first 256 characters of Unicode character-sets correspond to the 256 characters of ISO-8859-1.
Tip: All HTML 4 processors already support UTF-8, and all XHTML and XML processors support UTF-8 and UTF-16!
This entity reference includes mathematical symbols, Greek characters, various arrows, technical symbols and shapes.
Note: Entity names are case sensitive.