Changing your default website language
Changing your website language changes the character set used on your website, such as Western European, Japanese, or Russian.
Log in to your PayPal business account at paypal.com. Click the profile icon (
) on the top right side of the page. From the Business Profile menu, select Profile and Settings.
Note: If you do not see the profile icon on the top right, select Profile which appears in the top menu when the My Account tab is selected.
From the left menu, click My selling tools.
Scroll to the bottom, and under More selling tools click PayPal button language encoding. The Language Encoding page opens.
From the Your website’s language dropdown menu, select an appropriate setting.
Click the Save button.
https://developer.paypal.com/docs/classic/admin/checkout-settings/#configuring-language-encoding