Adding language detection
Now that we have added languages, we need to have a process to identify which language a given request uses. From the Languages
page, select the Detection and selection
tab to configure these settings. There are a number of different options available to select. Starting from the detection method at the top, Drupal will attempt each enabled method until one returns a value.

Language detection settings
Account administration pages
If Account administration pages
is selected, then each user will see an option to choose which language is used to display the administrative section. There is an option for No preference
, which will move on to the next language detection method. This language will be used on any routes that have the attribute _admin_route
.

User language settings
URL
If URL is selected, you are able to use either a path prefix or subdomain to be checked for the current language. The default configuration is to use a path prefix that corresponds to the code for...