[header] How to know if someone is talking behind your back [title] Listen for backhanded compliments. [step] Pay attention to how the person you suspect of talking behind your back speaks to your face. Someone who talks about you behind your back is often angry or upset with you. 
These emotions can come through in how they interact with you, such as thinly veiled jabs or backhanded compliments. [substeps] Even if the someone negates their nasty comments with a, " just kidding, " it may be that they are having trouble hiding their anger.