All, or certainly most, of my teachers kept on telling us to say if we didn't understand what they were on about. They were not being patronising. It's OK not to understand and not to be understood. It's also OK to say you don't understand and to say that you think someone hasn't understood you.
Isn't it? 
It always has been in my world.
This weather is getting me down. Is it May or March?
Why do hospitals, most of whom have large catchment areas, make accessing them so difficult?



that's interesting!' (My children rumbled that one years ago!)