Interpretation and understading of text

The success of undestanding a statement (in its context) is often a case of being find the right interpretation of the statement, but certainly this is not the only problem.

This is very easy to overlook when a teacher or document writer is writing a text:

the writer does not always notice that the text can be interpreted in many ways.

The above statement is not world shattering but we are trying to get a pretty comprehensive list of causes of lack of understanding.