To add multiple files to the file list, click File >> Open. Select the files that you want to convert to audio format and click on the open button. All files will be listed in the File List.

Select the files which you would like to convert to audio from the File list. Go to the ‘Speak’ menu and select the Convert Selected Files to Audio option. Adjust the audio properties and click on the OK button to start the conversion. This way all the selected files will be converted to audio format.