I only realized that dutch people are handful communicators when moving abroad. Apparently I do it unconsciously all the time.
For example we gesture when something tastes good and I don't even say "tastes good" out loud i just wave my hand next to my cheek. But quickly learnt that people think you're crazy in the head instead of complimenting the chef.
Now I wonder if mixed Italian-Dutch children have two different forms of communication by gestures. Would be interesting, especially since neither are true sign languages.
Eating only half a pepernoot and putting it back in the bowl is crazy behavior.
In this case the gesture is to not speak with a mouth full of food, which is understandable.
Needs the sound! Otherwise, even other Dutch people will look crazy at you. :)
I also learned in an awkward way that waving my hand next to my cheek isn't an international sign for lekker. I moved to Canada about 20 years ago, and still sometimes do it, but apparently here it means you're signaling that someone is a little bit crazy.