From Xojo Documentation
Uses the built-in speech synthesizer to pronounce the passed text string.
|phrase||String or Variant||Text string to be passed to the speech synthesizer. Speak will accept any variant that can be expressed as a string.|
|Interrupt||Boolean||Optional interrupt flag. If set to True, the call will terminate the previous calls to Speak. If omitted, False is assumed.|
Speak takes a string (or any variant that can be expressed as a string) and uses the Windows or Macintosh text-to-speech engine to speak the text. The speech is asynchronous, allowing normal program flow to continue. By default, subsequent calls to Speak before the first call has finished will queue up and speak after the completion of the previous call. If the optional interrupt flag is used and set to True, the previous Speak calls will be stopped immediately.
On Linux, Speak uses the eSpeak library which is installed by default on Ubuntu 10.04 and newer.
System.Speak("Please enter some text in the field!")