Overview: The language that the portal is displayed in depends on the following hierarchy, with the languages at the top of the list taking precedence over those at the bottom:
Component (iview) language (defined in the portalapp.xml)
Portal Mandatory language (defined in the prtDefault.properties)
User language (defined in the user’s profile).
Request language (defined by the browser).
Portal Default language (defined in the prtDefault.properties)
System Default language (default locale defined by the OS).
Example: for example, if you have your portal user language (as in point 3) set to Czech, but the language of the iView that is the logon page (as in point 1) set to English, that logon page will be displayed in English.
Property Location:Regarding the navigation path for the prtDefault.properties kindly refer to the SAP Documentation outlined below which provides a detailed summary and walkthrough regarding the language settings.