IMO if we'd been trained not to express emotion for 20 years or so, we could labour quietly - this used to be the case, cf The Light Years by Elizabeth Jane Howard, American Way of Birth by Jessica Mitford - both describe themselves/their characters being actively unable to express pain vocally due to years and years of training otherwise. Well, I'm pretty glad that has changed tbh, it sounds exactly like that classic kind of nightmare where you are enduring total terror and can't say a thing.
I posted on a thread here before that I am unconvinced that lack of noise achieves anything in childbirth, though a doctor pointed out that pushing requires pressure in the abdomen which can't be held without being silent. Since I didn't have to push (I was trying to hold the bugger in most of the time, while howling) this all seemed a bit pointless to me.
Organised noise IMO is an excellent accompaniment to labour. It's almost like cheering yourself on, while letting your audience companions know in no uncertain terms that you are the one who is going through something unusually tough.