Spell check bubble in email body is distracting, how do I turn this off?

Spell check bubble in email body is distracting, how do I turn this off?

Hey guys, 

This new feature that places a spell check bubble in the top right corner of the email body is distracting. Spell check is supposed to work quietly behind the scenes and notify me only when I spell something wrong by applying a red underline to the word. This bubble is a ridiculous distraction. 

How do I turn this off?