The Stoneage translator is a demo applet which uses the Embedded GF Interpreter and the GF stoneage grammar to very simple sentences between a number of languages.
The source code for the applet is included with the Embedded GF Interpreter source code.
You need a Java 1.5 plugin to run this applet.
If you do not have access to a Java 1.5 plugin, you can at least look at the pretty stoneage translator screenshot.
You can also run this program as an application. Download translate-stoneage.jar and run it with > java -jar translate-stoneage.jar