Slander, backbiting, holding one’s tongue and leaving that which does not concern one…

Is there a simple way of telling if one is hearing slander? It seems that speaking ill of a person is permissible sometimes and I can't usually tell the difference between what is permissible and what is not with regard to this. As a result I have trouble stopping people from speaking ill others.

Assalamu Alaykum wa Rahmatullah,

Please see the following links:

Fiqh for the Righteousness: The prohibition against backbiting & the command to guard the tongue (Riyad al-Salihin by Imam al-Nawawi)
http://www.sunnipath.com/resources/Questions/qa00000780.aspx

The Rules of Backbiting
http://www.sunnipath.com/resources/Questions/qa00000211.aspx

Backbiting the unknown?
http://www.sunnipath.com/resources/Questions/qa00000189.aspx

Some Fiqh of Speech: Mentioning Another Negatively Thinking the Listener Does Not Know Them
http://www.sunnipath.com/resources/Questions/qa00000217.aspx

Backbiting, Lying, & Busying Oneself with the Beneficial
http://www.sunnipath.com/resources/Questions/qa00000188.aspx

What does it mean, "Leave that which does not concern you?" If I am interested in something, doesn't it "concern me?"
http://www.sunnipath.com/resources/Questions/qa00000050.aspx

Repentance, Talking About Past Sin, and Avoiding That Which Does Not Concern One
http://www.sunnipath.com/resources/Questions/qa00002086.aspx

Wassalam
Hanafi Fiqh Staff