What do you mean?

I know I meant what I said, but did you understand what I meant?.
The spoken language is mainly what we use to communicate, along with facial expression and body language. It is not perfect, but it is all we have.
The degree of understanding varies with the concept being communicated.
"I'll have Big Mac, fries, and a medium coke" is going to yield pretty predictable results; well I suppose as long as you are actually at McDonald's.
On the other hand, if I say "I'm sorry" it could be interpreted as meaning "omg! I feel so bad that I hurt your feelings, I will never do that again" and actually have been intended as " ffs, I am tired of talking about this, time to change the topic". Or vice versa. How would you know?
I wonder if we were all telepaths, if it would be easier or harder. In a crowded room would the thoughts all be reduced to a jumbled murmur, or would they jostle for attention? Would they be organized and understandable or snatches of phrases mixed with images? Would I really want to know what others have on their minds? You know what I'm thinking; probably not.