Hello Morac,
In indirect speech or reported speech what the speaker does is telling in another way what another person has said, I mean, we refer to a past fact. Therefore, the most important
change which takes place when reporting something said by another person, is the verbal form. Therefore, the backshift is not related to the reporting verb.
However, there are some exceptions to this general rule, in this case, in statements:
- When we talk about routines or general truths, about things that remain true at the time of reporting them, then we keep the present tense.
- When the speaker talks about a future fact which has not happened yet at the time of reporting it, we have to keep the simple future form too.
- If we report words immediately after they have been said, for instance, when someone hasn �t understood something and another person repeat those words said by another one.
But if you are interested in knowing more about grammar in general, or reported speech in particular you should get:
Grammar in Use Intermediate or Advanced Grammar in Use by Raymond Murphy.
You should also watch Jennifer �s wonderful videos about this topic:
I hope all this information helps you!!
INMA ALC�ZAR