International Components for Unicode is described as '(ICU) is an open source project of mature C/C++ and Java libraries for Unicode support, software internationalization, and software globalization. ICU is widely portable to many operating systems and environments' and is an app in the Development category. There are three alternatives to International Components for Unicode for Linux, Mac, Windows and BSD. The best alternative is GNU gettext, which is both free and Open Source. Other great apps like International Components for Unicode are Pango (Free, Open Source) and Graphite (SIL) (Free, Open Source).
Graphite is a programmable Unicode-compliant smart-font technology and rendering system developed by SIL International as free software, distributed under the terms of the GNU Lesser General Public License and the Common Public License.