The Ruling of speaking in the Toilet,

Shaykh Bin Baaz (rahimahullaah) was asked regarding the ruling of speaking in the bathroom while using the toilet. 

He (rahimahullaah) replied: 

“If there is a need for it then it is okay, but if there is no need then it is better to leave off. If it is necessary to call someone, or say “do this and that”, then there is nothing wrong in it.”

Source: http://www.binbaz.org.sa/mat/20858

Also Shaykh Muqbil (rahimahullaah) gave a similar fatwa, as found in his book, ‘Qaaratul Ashritah ‘ala Ahlil Jahl wa-Safsatah’.