Even if verbal communication isn’t an issue, there can be a huge gap in understanding/relating to each other due to differences in generation and experiences growing up. I had no issues communicating with my parents in Mandarin Chinese, but certain experiences my parents had as kids/young adults were completely different from my childhood/young adulthood.
And people are quite variable in their willingness/ability to try making some effort in understanding the other.
Especially when there’s the possibility one may never fully comprehend the experience of others because they’re so greatly different and visceral that one literally had to be there to get the full experience…and that’s not always advisable considering what some of those experiences were…