my %res;
foreach my $word (@rw) {
  $res{$word} ||= do {
    my $re;
    $re .= $translations{$_} for split //,$word;
    $re;
  }
}

##</code><code>##

my $re;
$re .= $translations{$_} for split //,$word;
$re;

##</code><code>##

join '', @translations{ split //, $word };