A very powerful and useful feature of KooRaRoo is audio stream language matching to your preference.
Let's say your first language is English, but you also understand Spanish and you have a video file with multiple audio streams. Once you set your audio language preference in KooRaRoo's device properties to be "eng,spa", it'll pick and use audio streams from the file that match the priority of your languages.
If the file doesn't have English, but has Spanish, then that stream will be used instead of a language that you don't understand at all.
It may sound complicated, but it works behind the scenes and once you tried it, you'll be surprised how you ever lived without this