I live in a place where there are a lot of cultural differences. So, I assume German may also have cultures or habit that may differ from mine and some that are the same. So, here are some questions about body languages:

 1. Nodding means to agree in my place but it means to disagree in some
    places, what about in German?
 2. What about head shake?
 3. Are there specific words for those action? If I use **schütteln** for **head shake**, would
    it be correct as shaking hand also use the same word.