Interesting. This text shows really well the paralinguistic nature of those gestures. On one hand they aren’t simply meaningless “fluff”, they do convey info, to be taken alongside the linguistic info from the spoken channel; but on the other hand they aren’t language proper (unlike, say, a sign language), as they’re mostly mimetic and lack structure.

The fact they become more mimetic (image-rich) while teaching children reinforces it, IMO.

The two groups were chosen because previous research suggests Italians come from a more ‘gesture-rich’ culture, while Dutch speakers tend to use fewer representational gestures overall.

Relevant to note plenty Italian uses gestures all the time. At least when speaking in Italian; and sometimes, if you don’t get the gesture you won’t get what’s being said.

For example. Let’s say Tizio tells Caio “Sempronio says the Moon is made of green cheese”, while Tizio points to his own eye. Without the gesture, Caio might take Sempronio as a reliable source of info, or assume Tizio believes so; but the gesture implies “watch out” = “Sempronio is bullshitting, I’m not fooled”.