Medium Season 7 Episode 7 (Medium s07e07) with title “Native Tongue” aired on Friday, November 5th 2010 at 08:00 pm via CBS Network.
Here is summary for Medium Season 7 Episode 7 :

Suddenly unable to understand the spoken word, Allison’s marriage shows signs of strain and she develops an unexpected friendship with a linguist. Unable to communicate with his wife, Joe reaches the limits of his patience being married to a woman who is a slave to her visions.