Spell check not working in Gmail : Mac OS X

Recently I encountered that while composing an Email on Google's Gmail, no spellcheck warnings were displayed for incorrect spelled words. I found that the reason for this was the language settings in Mac OS X (working on Yosemite) Spelling and Grammar, let's see how to fix this,

1. Open Gmail Compose a new Mail Screen.
2. Right Click on the body section and Select: Spelling and Grammar -> Spelling and Grammar
3. Now if you see the Language dropdown with Automatic by Language, just change it the language you prefer.



Select U.S. English


4. Close the window.
5. You must now see that the incorrectly spelled words are underlined as red again.