I'm currently using Ubuntu 18.04 and Okular for viewing pdf documents. I thought it would be convenient if I could use the text to speech feature. I tried following all the instructions given here: http://freesoftwaremagazine.com/articles/listen_your_books_epub_pdf_okular/ (which was the only source I could find online) and I'm yet unable to get the text-to-speech feature working. Can you please tell me what should I do to get this working? If it is not possible because it was deprecated, can you please recommend a good alternative?
I tried opening the application from the terminal to listen to the audio. This was the output on the terminal when I selected a part of the text and clicked "Speak Text":
using null output device, none available
qt.speech.tts.flite: "Failed to start audio output (error 1)"
