sub complaint { "Please be sure that $_[0] is installed first" }
print complaint("XXX");

##</code><code>##

sub complaint {
my %r = (
    en => "Please be sure that $_[0] is installed first",
    fr => "Veuillez źtre sūr que $_[0] est installé premier"
);
$r{$lang}
}

# ...
$lang = "en";
print complaint("XXX");