DP and I have been together almost 14 years since mid teens, so very in sync with each other IMO.
for years, ive been nattering away to myself in my head and he hears me. Im 100% not saying anything outloud and absolutely positive of this.
One example, we were driving and he hadn't yet put his seatbelt on, and i commented on it in my head, he looked at me and said 'it's fine, ill put it on now". Again, i didn't say a thing.
Generally, im pottering about, going through a to do list or something, and hell ask what i said, again, knowing i havent uttered a word or even moved my lips!
Sounds bonkers i know, but its happened as long as I can remember!