Loki communicates (I wouldn't call it listening...ha) with me the best. He and I did 2 years of training classes so I know the most of his "words" and understand him the best. If someone else (like my mom or husband) gives him the proper command he will do it. And he will perform for anyone for a treat.
Sammy did 1 class with me, but I swear she and my husband have their own language. She definitely listens to him more than me.