libmime is a MIME parser in the same vein as Expat, the stream-oriented XML parser. As input is fed to the parser, events are generated which an application can catch by registering event handlers. Such events include the Unix From_ line, start of entity, end of entity, entity boundary, header, end of headers, and body. libmime supports MIME message editing through a delta mechanism. Edit contexts are instantiated and changes applied to specific contexts. Edit contexts can then be expressed in standard unified diff format which, when applied to the input source stream, will result in the new message.
Expose is a PHP template engine. It supports server and client-sided caching, a plugin system (to simplify common tasks like inserting a date picker) and internationalization (to write templates in multiple languages using external translation files). Unlike most template engines, Expose's template script language is based on PHP itself, which means you don't have to learn a new syntax. You can use most of the PHP language elements and functions in the way with which you're familiar.
Flexible Localization is a .NET/Mono library for string-based user interface localization. It offers a hierarchical structure (which can be partially loaded) to organize the strings, as well as support for several independently-localized modules. Localization files are validated against a localization declaration which defines the actual strings that are expected to be in the localization files. The strings themselves can be parametrized and evaluated based on expressions (i.e., different strings can be returned by a localization, based on parameter values).
Intlize allows the developer to use catgets without its normally bulky syntax and without having to mind the details of correct indices. Catgets is the built-in internationalization suite of C compilers. Alternatively, Intlize can produce a compact file format optimized for fast access. Intermediate files are in gettext po format, so there are many comfortable tools available to do the translations. Runtime files are provided for C and C++ and for both catgets and intlize native support.
OmegaT is a translation memory application intended for professional translators. It does not translate for you (software that does this is called "machine translation"). It features fuzzy matching, match propagation, simultaneous processing of multiple-file projects, simultaneous use of multiple translation memories, and external glossaries. Document file formats include plain text, HTML, and OpenOffice.org/StarOffice. It has Unicode (UTF-8) support (can be used with non-Latin alphabets). It is compatible with other translation memory applications (TMX Level 1).
LanguageSys is meant to internationalize your applications. It handles the access to language files, which are based on an INI style. It is possible to precompile the language files to increase the speed of processing. This system is focused on being highly object-oriented, so it makes the language aliases aviable as member variables of the own class. It contains a system to fetch a list of all the available languages by a given directory where the language files are located. A distinction of languages is drawn as RFC1766 recommends. Examples, documentation, and a simple script to precompile your language files are included.