[check The politics of typography before applying SIL-OFL]
The SIL-OFL is a free license specifically developed for (multi-lingual) fonts. These are the four freedoms guaranteed through the Open Font License (similar to other Free licenses):
* Use: the freedom to use font software for any purpose. (freedom 0)
* Study and adaptation: the freedom to study how font software works, and adapt it to your needs (freedom 1). Access and rights to the source code is a precondition for this.
* Redistribution: the freedom to redistribute copies of the font software so you can help your neighbor (freedom 2).
* Improvement and redistribution of modifications: the freedom to improve the font software and release your improvements (freedom 3), so that the community benefits. Access and rights to the source code is a precondition for this.
Applying an Open License to your font is made easy with the Open Font License. See this FAQ to find out how it works.