Mine

use Lingua::Identify qw/langof/;
$filename = $ARGV[0];
open( FILE, "< $filename" ) or die "Can't open $filename : $!";

foreach $line (<FILE>) {
push @lang, $line;
}

  my $text = join "\n", @lang;

  # identify the language by letting the module decide on the best way
  # to do so

  my $language = langof($text);
print "$language\n";