We will provide instructions on how to let your robot speak ROILA soon. We will use the free and open source Festival software.
Please bear with us, we are working on writing a technical primer/manual to enable you to get Text to Speech going for ROILA using Festival. It should hopefully be available on the ROILA website soon (Update: August 23, 2010). In the meanwhile you might want to explore our initial efforts with Text to Speech for ROILA using Festival here.