Speech is silver;silence is gold......... which that means silence is better than speaking at the situations that the person has nothing to say ,so it's better to him to say nothing than speaking many words that has no sense.......another reason: you can't learn anything if your running your mouth, but if you just sit back and observe and listen you'll be amazed at what you learn from being quiet..
There is an Arab proverb that says talking too much cause a person in the wrong
كثرة الكلام توقع الشخص فى الذلل"الخطا"