When you double click on the respective system in the SAP login pad, you will get the SAP login screen, where you need to enter your user ID and the password. In the same screen you might have seen a space to specify the language. If you're working on a SAP system where you have multiple languages installed, the default language that was setup by the Basis team will appear here.
Let's say; default language is setup as "IT" in your login screen and you always have to change it to English language (EN) before login. Today we will discuss how you can change this default language setting.