code: private String[] getInitialPromptSegments() {
          String value = Optional.fromNullable(getParameter(SignalParameters.INITIAL_PROMPT.symbol())).or("");
          return value.isEmpty() ? new String[0] : value.split(",");
      }
docs: The initial announcement prompting the user to either enter DTMF digits or to speak.
  <p>
  Consists of one or more audio segments.<br>
  If not specified (the default), the event immediately begins digit collection or recording.
  </p>
  
  @return The array of audio prompts. Array will be empty if none is specified.