Praise be to Allaah. 

It is possible to talk to the jinn, but finding about unseen matters and what is in people’s hearts is haraam.Usually those who use words and phrases of the Qur’aan in order to gain control over the jinn use ways that are not Islamic. Using the jinn is a power that was given only to Sulaymaan (peace be upon him). Hence when the Prophet (peace and blessings of Allaah be upon him) wanted to tie up a jinn whom he had overcome during his prayer, he remembered the du’aa’ of Sulayman and did not do that.

So you should try to advise these people and if they respond, all well and good; otherwise the safest thing to do is to leave them alone and not speak to them.

Ahl al-Kitaab (the People of the Book) are the Jews and Christians.

It is OK to speak with the jinn if this happens without you seeking it, and in fact it is mustahabb to call them to the religion of Allaah and to adhere to His sharee’ah, just as you call people. It is not advisable to read books or to recite Qur’aan for this purpose, because the Qur’aan was not revealed for such things; it was revealed to be a light and a guide in the life of the Muslim, so that the Muslim can follow it, obeying its commandments and avoiding that which it forbids.

With regard to the angels, the Prophet (peace and blessings of Allaah be upon him) and other prophets saw them, and some of the awliyaa’ (close friends of Allaah) spoke with them, as it was reported from ‘Imraan ibn Husayn (may Allaah be pleased with him) that the angels used to greet him with salaam until he started to use branding (cauterization for medical purposes), then they stopped. When he stopped using branding, they started to greet him again. And Allaah knows best.