Graphite (SIL) is described as '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'. There are three alternatives to Graphite (SIL) for Linux, Mac and Windows. The best alternative is GNU gettext, which is both free and Open Source. Other great apps like Graphite (SIL) are International Components for Unicode (Free, Open Source) and Pango (Free, Open Source).
International Components for Unicode (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.