How you can go a variable into an add_filter() operate?

I’ve this code right here:

$pageLanguage = strtolower($pageMetadata["language"]); 

$languageArray = array ("afrikaans" => "af", "dutch" => "nl", "french" => "fr", "german" => "de", "spanish" => "es"); 

$updatedLanguage = $languageArray[$pageLanguage];

add_filter('locale', 'change_my_locale');
operate change_my_locale( $locale ) {
  $locale = $updatedLanguage;
  return $locale;
}

I wish to know tips on how to go the variable $updatedLanguage into the change_my_locale() operate please?