How do I apply a promo code? If you have a promo code for Linguix Premium, follow these steps to apply it: If you already have an account, sign in at linguix.com. Navigate to https://linguix.com/promokey and apply your code. In the case when you do not have an account yet, first sign up using this link. Then navigate to the Promokey page and apply your code. Related articles Linguix Business: Main Features How does Linguix affiliate program work? How do I protect my Linguix account?