I can’t tell you in my own words how to turn off retweets but Kristi Roddy writing online at Techwalla.com in an article called “How to Hide Your Followers & Who You Are Following on Twitter” describes how to use a workaround do this in 7 steps: “(1) Sign in to your Twitter account using your user name and password. (2) Click ‘Settings’ in the menu bar at the top, on the right side of the screen. This will take you to the Settings menu. (3) Click ‘Design’ on the Settings menu, which is the last option. (4) At the bottom of the page, click ‘Change design colors.’
This gives you the option to change the colors of your background, text, links, sidebar and sidebar border. (5) Click the color block below the sidebar option, and change the color to whatever you prefer. (6) Click the color block below the links option, and choose the same color you chose for the sidebar. (7) Click the color block below the text option, and choose the same color you chose for the links and sidebar. The number of people you are following and the number of people following you will be invisible."