The Centre for Speech Technology Research, The university of Edinburgh

Festival Text-to-Speech Online Demo FAQ

What is all this "synthetic speech", TTS, speech synthesis etc...?

Synthetic speech is speech which has been produced by some artificial means (e.g. by computer software or some mechanical device) rather than by a real human.
Text-to-speech synthesis (TTS for short) is any system which takes text input and converts it automatically into audible speech, using any of the many speech synthesis methods.

Where can I find out more about Festival?

A good place to start for further information is the Festival project page.

Where can I find out more about speech synthesis?

Although not authoratitive, Wikipedia has a page on speech synthesis, which is instantly accessible and covers many aspects for the layperson. Another starting place is the comp.speech Frequently Asked Questions page.

How do I make this demo work?

There are three simple steps to using this demo:

I've done that but it still doesn't work!

There are several possible causes:

I've just been using the demo, but now it suddenly doesn't work - why is that?

Unfortunately, due to a few cases of abuse of this web demo, we have had to implement a cap on the number of synthesis requests which can occur in a certain time period. We've tried to set this high enough so that it doesn't interfere with legitimate use of the demo (i.e. by a human!). However, if you find you've been really engrossed in listening to synthetic speech samples and have used up your quota of requests and the demo no longer works, then just leave it a while and try again. If it doesn't work again after a few hours then please report this.

Why does it take so long?

Speech synthesis can be computationally expensive, depending on which voice is selected. If several people are trying to use the demo at once, things will slow down too. We only have limited resources to dedicate to this demo after all! There may also be delays in sending the synthetic speech over the internet to you (especially if you have a slow connection to the internet). Finally, we are currently investigating random delays which sometimes occur in our own network, which sometimes slows down data transfer to and from the machine which actually does the synthesis here.

Usage - how can this demo be used?

We provide this as an interactive demonstration of speech synthesis in Festival only. It should not be considered or used in any way as a "free service", e.g. using the underlying CGI scripts themselves, or access by any sort of automatic script is not permitted. On the other hand, if you are a human and you type in a bunch of short sentences to the web form to hear how the synthetic speech sounds, then that is perfectly fine.

Likewise, the synthetic speech produced is meant for personal, non-commercial use only. Using the synthetic speech for anything else than purely listening to it as a standalone audio file is not permitted.

If you are in any doubt whether what you want to do with this is acceptable or not, then please mail to ask!

I really like your demo, where can I download voice XYZ?

Since posting this demo we've been getting more and more mails asking where to find downloads for the voices featured to match the freely available Festival synthesis system itself.

In fact, we have previously made some of these voices available on a one-off basis to several commercial parties who have approached us. However, very few of the voices in this demo are currently publicly available directly as a download (whether for non-commercial or commercial use).

The good news, though, is that we're currently putting together a portfolio of dozens and dozens (really!) of voices which will be available to download shortly. Some voices will be available for commercial use only, some for non-commercial use only, and indeed some for both. We envisage all the voices currently on the demo will be available, with the addition of many more. When these are ready, we'll put a link in the demo itself, amongst other things.

In the meantime, if you'd like to discuss commercial licensing in a hurry, or would like to be notified when commercial voices become available, then please mail .

I love demo voice X and downloaded one with a similar name from Y. Why doesn't it sound the same as on the demo?

The system running on our demo page typically uses cutting-edge developments resulting from our most recent research. These features may not have made it to the free public releases yet. See the answer to the previous frequently asked question for more details.