yes, this is what I talked about in "1)" above. Your hash is permanent, you have to fill it only once, ever. You need two scripts:

This is the script you call once whenever your source file changes:

#!/usr/bin/perl

#script 1. Fills the hash 

use warnings;
use strict;
use DBM::Deep;

my $file_in_en=shift;
my %hash_en=to_hash($file_in_en);

sub to_hash {
my $file = shift;
my $db = DBM::Deep->new( "$file.db" );
$db->clear();
open(FILE, "<$file");
foreach $l (<FILE>) {
    my ($ngram,$line) = split /\t/, $l;
    push(@{ $db->{$ngram} }, $line);
    }
close FILE;
return $db;
}
[download]

And this is your search script:

#!/usr/bin/perl

#script 2. Search item in hash

use warnings;
use strict;
use DBM::Deep;


my $file=shift;
my $hash_en= DBM::Deep->new( "$file.db" );
print @{$hash_en->{'despite'}};
[download]

UDPATE: corrected the search script