A hash is inappropriate here. Your key is not a key at all. A key is a *unique* way of *identifying* something. A score is neither unique, nor an identity.

my @data = (
   [ 12, 'First line of text'  ],
   [ 25, 'Second line of text' ],
   [ 34, 'Third line of text'  ],
);

foreach (@scoreWords) {
   my $re = qr/\b\Q$_\E\b/i;
   foreach (@data) {
      $_[0] += $y while $_[1] =~ /$re/g;
   }
}
[download]

Update: I either missed the second part of the question, or the OP has been updated. Here's my updated answer:

my @data = (
   [ 1, 12, 'First line of text'  ],
   [ 2, 25, 'Second line of text' ],
   [ 3, 34, 'Third line of text'  ],
);

foreach (@scoreWords) {
   my $re = qr/\b\Q$_\E\b/i;
   foreach (@data) {
      $_[1] += $y while $_[2] =~ /$re/g;
   }
}

print("Line ${$_}[0] has a score of ${$_}[1]\n")
   foreach sort { $b->[1] <=> $a->[1] } @data;
[download]

my @data = (
   [ 12, 'First line of text'  ],
   [ 25, 'Second line of text' ],
   [ 34, 'Third line of text'  ],
);

foreach (@scoreWords) {
   my $re = qr/\b\Q$_\E\b/i;
   foreach (@data) {
      $_[0] += $y while $_[1] =~ /$re/g;
   }
}

print("${$_}[0]: ${$_}[1]\n")
   foreach sort { $b->[0] <=> $a->[0] } @data;
[download]

Update: Changed if // to while //g.

I'd reverse the nature of the hash and store lines as keys and values as the count.

use strict;
use warnings;

my @words = qw( alpha beta gamma );

my @lines = (
    'alpha comes before beta and gamma, but not alphabet',
    'beta comes after alpha; beta comes before gamma',
    'gamma is the last word',
);

my %count;

for my $line ( @lines ) {
    for my $word ( @words ) {
        my $c =()= ($line =~ m/\b\Q$word\E\b/g);
        $count{$line} += $c;
    }
}

print map { "$count{$_}: $_\n" } @lines;
[download]

Gives:

3: alpha comes before beta and gamma, but not alphabet
4: beta comes after alpha; beta comes before gamma
1: gamma is the last word
[download]

(I'm sure this can be golfed, but I think it's clearer this way.)

Update: reading ikegami's answer, we're both on the right track, but I think solving slightly different problems. I'm not sure which one is the one you want: a count of occurances of keys across all lines or a count of occurances of keys within lines. And do you want to count multiple occurances of each special word? My answer gives the count by line including multiple occurances.

Also, it reminded me to add \Q and \E for safety's sake, so I've made that change.

Update 2: For those who don't recognize it, see Perl Idioms Explained - my $count = () = /.../g.

Your data structure is malformed. You don't want the key to be the score, that is, something subject to change.

What happens if I bump up the score of something that was at 13 by two, but there's another sentence at 15? Or what if there's a sentence at 12, and one at 13, and the 12 one gets bumped up by 3 and the 13 one gets bumped up by two? What's going to happen with that data structure is that one or the other will get wiped out.

So first, we take your hash and replace it with a saner data structure:

my @scorearray = map { {score=>$_, text=>$hash{$_}} } keys %hash;
[download]

Now that that's done, what you ask is quite easy:

for my $word (@scoreWords) {
  my $qmword = quotemeta($word);
  my $regexp = qr/\b$qmword\b/;
  for my $scorebit (@scorearray) {
    $scorebit->{'score'} += 1 if $scorebit->{'text'} =~ $regexp;
  }
}
[download]

You can even print it out in a pretty table:

printf "%-7s%s\n", "Score", "Value";
for my $scorebit (@scorearray) {
  printf "%5d  %s\n", $scorebit->{'score'}, $scorebit->{'text'};
}
[download]

@/=map{[/./g]}qw/.h_nJ Xapou cets krht ele_ r_ra/;
map{y/X_/\n /;print}map{pop@$_}@/for@/
[download]

I think the Map function may suit my needs.
But I dont understand fully what's going on Fizbin's script. Could someone explain further how to get the values into the scorearray or suggest a tutorial. I am very new to perl as you might gather and am finding these expressions difficult to follow.
Thanks to all for their help.

This is buggy as far as scoring, but the idea is here.

#!/usr/bin/perl -w
use strict;

my $text = qq|If you have a question on how to do something in Perl, o
+r you need a Perl solution to
an actual real-life problem, or you're unsure why something you've tri
+ed just isn't 
working... then this is the place to ask.
However, you might consider asking in the chatterbox first (if you're 
+a registered user).
The response time tends to be quicker, and if it turns out that the pr
+oblem/solutions are
too much for the cb to handle, the kind monks will be sure to direct y
+ou here.|;



# build lines hash
my %lines;
my $k=1;
for (split(/\n/,$text)){
    $lines{$k}=$_;
    $k++;
}



# score hash
# put your words here, and the value for each
my %score_guide = (
    'for'=>1,
    'the'=>1,
    'if'=>2,
    'you'=>3,
    'moguai'=>40
);


# this will hold key= line num, val= score
my %score_results =();


# score each line
for (keys %lines){
    $score_results{$_} = score_line($lines{$_});
}


# feedback
for (keys %score_results){
    print "line $_ score $score_results{$_}\n";
}







sub score_line {
    my ($string)=$_[0]; # 
    
    my $score=0;
    
    
    for (sort keys %score_guide){
        
        while ($string=~s/\b\Q$_\E\b//i){ # corrected by ikegami
            $score+=$score_guide{$_};
        }
    }
    
    return $score;
}
[download]

output:

[leo@mescaline ~]$ perl scorelines.pl
line 1 score 8
line 2 score 6
line 3 score 1
line 4 score 9
line 5 score 4
line 6 score 6
[download]

/\b$_\b/
should be
/\b\Q$_\E\b/
since the OP said he had an array of words (as opposed to regexps).