Fix typo

README.md

@@ -32,7 +32,7 @@ twitter.getRequestToken(function(error, requestToken, requestTokenSecret, result
 	}
 });
 ```
-If no error has occured, you now have a `requestToken` and a `requestTokenSecret`. You should store them somewhere (e.g. in a session, if you are using express), because you will need them later to get the current user's access token, which is used for authentification.
+If no error has occured, you now have a `requestToken` and a `requestTokenSecret`. You should store them somewhere (e.g. in a session, if you are using express), because you will need them later to get the current user's access token, which is used for authentication.
 
 ### Step 3: Getting an Access Token ###
 Redirect the user to `https://twitter.com/oauth/authenticate?oauth_token=[requestToken]`. `twitter.getAuthUrl(requestToken, options)` also returns that URL (the options parameter is optional and may contain a boolean `force_login` and a String `screen_name` - see the Twitter API Documentation for more information on these parameters).