If what you want is to end up with a histogram-like structure, stuff the found vowels into a hash. You may try something like this:

my $phrase = 'There once was a doggy in the window. I went into the st
+ore and inquired about the price, the doggy was too nice to ever thin
+k twice, so now I have a doggy to care for.';

my %vowels;
while ($phrase =~ /([aeiou])/gi) {
    $vowels{lc $1}++;
}

use YAML;
print Dump \%vowels;

__END__


the output would look like

---
a: 8
e: 17
i: 11
o: 15
u: 2
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