Unlike most of the previous songs on Vulnicura, which deal with the tumultuous dissolution of Björk’s relationship with Matthew Barney, “Mouth Mantra” is about a three-week period after vocal surgery in which Björk wasn’t able to speak.

As Björk stated in a post on her website in November 2012, doctors had found a polyp on her vocal chords four years before. She wrote on her website:

I decided to go the natural way and for 4 years did stretches and tackled it with different foods and what not.

However, Björk said she became intrigued by “hi tech laser stuff”, and opted for surgery. After the operation had taken place, she was unable to make noise. In the song, she expresses her feelings of sadness and inability during those weeks of silence.

During this period of time, she was also forced to cancel many dates of her expansive and critically acclaimed Biophilia Tour.