In English there's certainly a difference, but it's subtle.
You're so strong:
This could be a statement of disbelief, like someone just picked up a golf cart and his friend is shocked.
This also sounds somewhat flirty, like something a girl would say to an attractive guy at a gym
The level of strength involved is also potentially quite relative, as 'so' tends to mean 'far more than I thought'
You're very strong:
This sounds somewhat more matter-of-fact, and seems far less likely to be used in typical conversation. If someone tells you "You're so strong," you might reply with "thanks," but if someone tells you "You're very strong," it would seem more awkward, as in "How do I reply to you stating as a fact that I am strong?"
This also sounds more definite. While 'so' tends to be relative to previous belief, as stated above, very is relative to the general population, or just typical expectations, making it's meaning more consistent when said to multiple people.
I realize this is a very subtle difference, but this is the "feel" these sentences present, even if it takes some thought to uncover the nuances of the phrases.
In summary, yes, there's definitely a difference between the two in English, but what's the difference between them in German?
The difference might be in the emotion which preceds that statement. As a native Swedish speaker, "You are so strong (Du är så stark)" is a sign of surprise. On the other hand, "You are very strong (Du är väldigt stark)" has more to do with affirmation, the person already knew you were strong. The reason for using Swedish as an example is due to the close relation in translation. Maybe it is the same with English though, I do not know.
"So" in German here seems to mean the same as "so" in english, but during this lesson it teaches that "so" in german means "that", e.g. nicht so = not that. Can someone explain why it does not mean "that" in this sentence? and how can we recognise whether it means so or that?
Well, from what I know, the german "so" is like the "so" in "I think so". There was thing one thing that made me understand the concept pretty much. Wo? Da. Womit? Damit. Wie? So. So, it's like "like that" rather than only "that". Aside from that, I guess Germans use "so" as in "so" in English as in this sentence. Actually, you know what, http://yourdailygerman.com/2013/11/20/meaning-german-so/ he explains it way better that I can :T
While "severe" could be used to describe a person, you wouldn't normally say that to their face. If you're looking for a severe person, imagine Severus Snape or Delores Umbridge. A strong person could be mentally or physically strong, but either way would be a compliment. While you could call a severe person strong, you wouldn't call a strong person severe unless they were both.
Hope this made sense ;)
i listened to this several times, and it sounds like she's saying "zu stark" and not "so stark". At first I assumed it was "so", but the voice sounded more like "zu", so that's why I listened to it several times. Very frustrating, especially since it seems everyone else heard "so".
That's actually what I put the first time - the German speech sounded like that to me. It's slightly more clear with the slow-mo speech but I feel like it can still be confused, especially since 'Du bist zu stark' is a real sentence (and truthfully, it's like the typical Duolingo sentence - it sounds a bit silly and you probably wouldn't ever use it in real life but it is technically correct and you COULD find random certain circumstances to make it applicable.)
I guess "stark" can mean "severe" only in specific situations, for example, when referring to a "severe storm" (which I'd guess could be translate as "starker Strum" or "schwerer Strum). "Severe" as a personal attribute would be "schwer" IIRC. (Take my answer with a grain of salt, however, since I'm not a native speaker neither fluent in German yet.)
Is anyone else experiencing not hearing the first word when you play the normal speed audio in the "Type what you hear exercises"? I played it several times and only heard three words that I thought were "Bist du stark". This happens quite often actually. I'm using Android lollipop on Galaxy S4.
Might be your system. Sometimes, on my school-issued chromebook, it won't play regular speed at all and have to listen to the slower version. It's probably just a bug.