At least in the region of Brazil where I come from (triângulo mineiro, Brazilian Texas I'd say.. we are considered the farmers of the Brazil also because of our accent ) people have a very weird way of saying 'no' to others. I discovered that it was weird after moving to the Netherlands where people are unaware of it. It's like that: we suck the air in our mouths so that when we release our tongues from the roof of our mouths we make a noise. We do that twice and a bit fast. And this is an informal way of saying 'no' to others. I'm very curious to know where this comes from. I don't even no the name of it and I think most people that use it are not aware of its weirdness.
It seems obvious to me that this style of negation is related to one used by Arabs but also by many other people living around the Mediterranean. It's the same sound, not necessarily repeated, but accompanied by a characteristic head movement. You can see it here as the first example.