Check if a given language is valid or if exists.
valid_language( string $lang [, bool $file_check ] ) : bool
$lang (string) (Required) The name of the language.
$file_check (bool) (Optional) Intended to be used when enabling languages in Admin Panel. Default value: false
(bool)
if (valid_language('English')) {
echo 'The language is valid and ready to use.';
}