All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His Slave and Messenger.
First of all, we would like to stress that a Muslim should not preoccupy himself with the Jinn or live in fear of them. The Jinn are weak creatures who have no power except for what Allaah has imparted to them. They are under the full control and dominion of Allaah and they cannot harm anyone except by the permission of Allaah. Therefore, Allaah, The Exalted, says (what means): {... But they do not harm anyone through it except by permission of Allaah...}[Quran 2:102]
Allaah has prescribed for us a means of seeking refuge in Him from the evils and plots of the Jinn. He revealed Al-Mu‘awwithatayn (Chapters 113 and 114 of the Quran) as a means for us to seek refuge in Him. Whoever wants to shield himself against their evils should turn to his Lord for He is the only one to protect him against their evils and harm. For further benefit, please refer to Fataawa 9591, 18310 and 5241.
It is not true that humans cannot speak to Jinn unless they appear in human form. ‘Abdullaah, son of Imaam Ahmad said: "I said to my father, 'Some people say that the Jinn do not enter the body of a possessed person.' He said, 'O my son, they are lying; the Jinn speak through the tongue of the possessed person.'"