I am a little Lost. What does Beta mean above a language?
It just means that the number of user-reported translation errors has not yet been reduced to acceptable levels to leave beta. It's basically a disclaimer that the exercises might be a little rougher around the edges than they would be in a course that graduated from beta. Anyone can do a beta course.
basically thats its not the final version of the course and it's being worked on, so maybe you're bound to run into minor bugs, maybe low quality features and stuff like that, so yeah basically that its being worked on and is not the final, polished version. hope this answered your question