I started the Klingon course thinking that it would be cool to learn a "secret language", but there's no sound. Why? Is there a possible way to get sound or a pronunciation guide???
If you're using a phone, tablet, or other device, there is a Klingon Text-to-speech engine that you can download free from Google Play Store that will partially do the job. (I don't know if it's compatible with a desktop computer, or with all mobile platforms.) You can download it here:
However, be forewarned that this will not automatically read Klingon text aloud for you. Rather, it's more like a plug-in that works in the app, or in an internet browser, and you have to be able to select/highlight the desired text with your cursor. If you can do that (and it won't work with all sentences on the app; for example, you can't select word tiles), then you can select the option on the pop-up bar that says "Read Klingon text," and it will do so.
Further to this, on my Android device, this text-to-speech plug-in currently seems to have a bug which leaves off the last word of the sentence for some reason. This could just be a problem with my device, though. These are drawbacks, sure, but if you don't mind working around them, they do produce the desired effect. Once it's installed, and you figure out when and where it does and doesn't work, it's actually quite useful. And using it gave me the added benefit of having a couple of sounds I'd been pronouncing incorrectly corrected before I got the wrong pronunciation too ingrained in my head. :-)
Also, bear in mind that you can copy and paste, or type, any Klingon text into the Text Reader page as follows. This works on a desktop as well as on mobile, as long as you have access to a browser:
They're not nicely built-in options. But they do get the job done for a small amount of extra effort.
Finally, I also use the Sounds of Klingon page that DragonPolyglot recommended for basic pronunciation instruction, and for reference:
I hope you'll decide to try some of these resources. Qapla'!
For iOS devices, you can look for HIja': https://itunes.apple.com/us/app/hija/id1366951358?mt=8
Duolingo decided not to add sound (yet). Here are a few guides for Klingoon pronunciation:
Omniglot Klingon profile (IPA & pIqaD): https://www.omniglot.com/conscripts/klingon.htm
Klingon Institute sounds of Klingon: https://www.kli.org/about-klingon/sounds-of-klingon/
Pronunciation taught by the Klingon teacher from Germany: https://www.youtube.com/watch?v=SSfKSvB1evA
As you see, it's a little difficult to get the sounds of Klingon quite right at first, and I can understand the course not addressing it in lesson 1 however I do agree sound would help the course greatly.