If you just changed the settings and don't know how to return the Russian interface language, use the corresponding menu items under Settings. Click on the icon settings of the system that has the form of a gear and is located on the main screen of the system.
In the displayed list of settings, find the section Language & Input and tap on it with your finger. In the list, select the Language option. On the new screen, find the position of "Russian". Once the choice is made, the device will switch back to Russian language.
If the list of languages, no Russian, you will have to install localization. Navigate to the program Play Market, located in the main menu of the smartphone or on the main screen. In the search menu, enter a query MoreLocale2. A line search is at the top of the application window.
Among the obtained results, select the one which completely matches to your query. After that click on Install button and wait for the installation process. To monitor the installation you can use the top notification bar of the screen.
After unpacking the language pack go back to the home screen of the device by pressing the Central button of your HTC. Again, go to Settings – Language & Input. In the list of available languages to select "Russian" and restart the machine to apply the changes.
If after installing you have no keyboard in Russian, go to "Menu" - "Settings" - "Language and keyboard" - "international keyboard" and put a check in the Russian language. Setup the Russian language for HTC Sensation is complete.