One time when I was younger, my mom was talking to my grandmother on the phone, in Spanish. I could hear my grandmother on the other end too. They're both yelling. No idea what they were talking about, but I had to ask, something to the effect of, "Mom, are you angry? Why are you and grandma yelling?"

Nope, nothing was wrong. That's just how they talk to each other in Spanish. Weird. It also never occurred to me why I didn't notice until whatever age I was, a teenager in high school. It never really occurred to me that they were always 'yelling' while talking to each other until that moment.

There is the possibility that they really were upset and yelling, but my mother didn't often keep things from me (at least not as far as I know). I also noticed the yelling afterwards, so I'm confident that was me simply realizing that's how they talked after years of not noticing.