Change the language for Google products from Account Preferences. Google warns that you may need to clear the cache and the cookies of your browser for the changes to take effect.
To change the language, sign into your Google account from any of the Google services, open your Account Preferences, and click Language & Input Tools. Click Language, and click the gray pen icon. Choose a language from the drop-down list, and click Ok.
Different Google services may support different languages. You can add multiple languages to make Google display a page in another language you understand when your preferred language isn't available. To do so, click Add Another Language on the Language page, and choose a language from the list. You must select one language as the default.
If the language of a Google service remains the same after you save the settings, try clearing the browser's cache and cookies. To do so in Google Chrome, click the Chrome menu on the toolbar, click More Tools, and then click Clear Browser Data. Check Cookies and Cached Images from the list, choose Beginning Of Time, and click Clear Browsing Data.
To clear the cache and cookies in Mozilla Firefox, click the menu button on the toolbar, and click Options. Select Advanced, navigate to the Network tab, and click the Clear Now button next to Cached Web Content. Then navigate to the Privacy tab, choose Use Custom Settings For History from the drop-down list under History, and click Show Cookies. Select all cookies, and click Remove Selected.
If using Apple Safari, click the Safari button on the upper left, open Preferences, and navigate to the Privacy tab. Click Remove All Website Data, and then click Remove Now.