This is a complicated question that linguists have broken down into smaller, more specific questions. I'm not a linguist though, so I can't tell you the ins and the outs of the various aspects of those discussions. But, I can give a good example (I think).

Since we're all familiar with English, have you ever noticed how specific the language is in regard to time? When speaking or writing English, it is generally clear when things are occurring. For example, I am now using the present progressive and simple present to express my thoughts. We also regularly construct sentences like, "I would have brought her lunch but I remembered her telling me that she would be going out for lunch with her boss".

Yes, this is entirely possible in other languages, but kind of difficult (no matter what the language) and perhaps might phrased more along the lines of, "I did not bring her lunch. Earlier, she told me she would go out to eat with her boss" which serves the same general purpose, but does not convey the idea of intent, the conditional nature of that intent, nor the idea of the future from a past perspective.

Language is inherently limited and imperfect. Perfect communication might be something like telepathy, where the exact meaning and feelings attached to meaning are flawlessly received and broadcast, but as things stand, that's not what we're working with. Notice how in English, it's entirely normal to ask someone to clarify what they mean, either in conversations in person, or in exchanges of text as in e-mail.