I am running Ubuntu 10.10 using Java 6 and can not get FreeTTS to output any audio. I have tried it now on 3 different computers and even asked a buddy of mine to try it on
I guess had the same issue on Ubuntu 12.04/OpenJDK-6, the execution get stuck in Voice.allocate() with no errors and no response. I tried using the Oracle/Sun JDK-6 instead of OpenJDK, and it worked fine.
P.S. Nice guide to install SunJDK on Ubuntu and configuring as default http://www.devsniper.com/ubuntu-12-04-install-sun-jdk-6-7/