open(DICT, "dictionary.txt" or die "Error: $!";
my @words = <DICT>;
close(DICT) or die "Error: $!";

@words = shuffle(@words); # assume shuffle is defined

my @new_words;

my @letters = (a .. z);
my @cnt = 0;

foreach my $letter (@letters)
{
  $cnt = 0;

  foreach my $word (@words)
  {
     if ($cnt > 100)
     {
        last;  # break loop, our 100 word is found
     }

     if ($word =~ m/^$letter/i)
     {
        $cnt++;
        push (@new_words, $word);
     }
  }
        
}