The default end-user language is typically set based on the user's browser settings or device settings. When a user visits a website or uses an application, the website or application can detect the language settings of the user's browser or device and display content in the appropriate language.
Most modern web browsers have language settings that can be configured by the user. The browser sends this language preference to the website, which can then display content in the user's preferred language, if available. Additionally, many operating systems and devices also have language settings that can be configured by the user. Applications installed on these devices can then use these settings to display content in the user's preferred language.
In some cases, the default end-user language may be set based on the user's location. For example, a website or application may detect the user's IP address or GPS location and automatically set the language to the primary language spoken in that region.
Overall, the default end-user language is typically set based on the user's preferences or location and can be automatically detected by the website or application.