Ensures that a given language code is valid.
Checks whether the given language code is one of the enabled language codes. Otherwise, it returns the current, global language code; or the site's default language code, if the additional parameter $default is TRUE.
$langcode: The language code to validate.
$default: Whether to return the default language code or the current language code in case $langcode is invalid.
A valid language code.
function field_valid_language($langcode, $default = TRUE) {
$languages = field_content_languages();
if (in_array($langcode, $languages)) {
return $langcode;
}
return $default ? language_default()->langcode : language(Language::TYPE_CONTENT)->langcode;
}