Set the current locale

This function behaves exactly the same way as PHP setlocale except for the following:

  • If the $locale argument is omitted, it uses the locale setting translated for the current user language.
  • You can optionally specify a CSV string of locales to try for the $locale argument.
  • You can optionally or a “category=locale;category=locale;category=locale” string for the $locale argument. When this type of string is used, the $category argument is ignored.
  • This method does not accept more than the 3 indicated arguments.
  • Any of the arguments may be swapped.

See the PHP setlocale link above for a list of constants that can be used for the $category argument.

Note that the locale is set once at bootup by ProcessWire, and does not change after that unless you call this method. Meaning, a change to $user->language does not automatically change the locale. If you want to change the locale, you would have to call this method after changing the user’s language from the API side.


// Set locale to whatever settings defined for current $user language

// Set all locale categories
$languages->setLocale(LC_ALL, 'en_US.UTF-8');

// Set locale for specific category (CTYPE)
$langauges->setLocale(LC_CTYPE, 'en_US.UTF-8');

// Try multiple locales till one works (in order) using array
$languages->setLocale(LC_ALL, [ 'en_US.UTF-8', 'en_US', 'en' ]);

// Same as above, except using CSV string
$languages->setLocale(LC_ALL, 'en_US.UTF-8, en_US, en');

// Set multiple categories and locales (first argument ignored)
$languages->setLocale(null, 'LC_CTYPE=en_US;LC_NUMERIC=de_DE;LC_TIME=es_ES'); 


// basic usage
$string = $languages->setLocale();

// usage with all arguments
$string = $languages->setLocale($category = 6, $locale = null);


$category (optional)int or string or array or null or Language

Specify a PHP “LC_” constant (int) or omit (or null) for default (LC_ALL).

$locale (optional)int or string or array or null or Language

Specify string, array or CSV string of locale name(s), omit (null) for current language locale, or specify Language object to pull locale from that language.

Return value

string or bool

Returns the locale that was set or boolean false if requested locale cannot be set.

See Also

Languages methods and properties

API reference based on ProcessWire core version 3.0.62