Reporting what someone has said 
can be a
difficult task in a foreign language.
Utterances can be made the
 subject of the
other utterances. 
They can be criticized, questioned, 
commented on, or simply
be reported. 
Language can be uses to refer to language. 
We can talk about talk.
This is true 
for all natural languages and is, indeed, 
a fundamental feature
whose absence 
disqualifies any sign system as a human 
language. However, there
are different 
ways of reporting the speech of another.
Direct speech is
the exact words that people say. Reported speech (or
indirect speech) is how we report the words. 
We
make changes when we report what people say, such as to the tense and pronouns.
When we report speech, we usually move the verb form one tense back,
so present verbs in direct speech become past verbs in reported speech.