Whats the differece between "fles" and "vless" in their prounciation? I heard "vlees".
Even if it is a common root, that does not mean they mean the same thing. The Dutch word "stoel"and the English "stool" have a common root, but you can't call a chair (stoel) a stool.
I think it has to do with Het & De words. So if a word like "Fles" comes up, it would be "De Fles", so it gets "Onze" whereas if you see "Het Kind" , it becomes "Ons Kind". I think this is how it is, any corrections are welcome :)