Well George I came up with the same number of 'patterns' but I didnt need a regex. I thought you might like to see it:

my $s='helloworldhellohellohihellohiworld';

#determine every substring in the original
my %hash;
for my $i (0..length($s)-1) {
    $hash{substr($s,$i,$_)}++
        for (1..length($s)-$i);
}
#filter out singles and the chars
%hash=map {
           ($hash{$_}>1 && length($_)>1)
            ? ($_,$hash{$_})
            :()
          } keys %hash; #yes this is how i format maps
                        #and ternary ops.. :-)
#print the results
use Data::Dumper;
print Dumper(\%hash);
[download]

Id love to know how the OP wanted the computer to tell that 'hello' is a word but 'elloh' isnt... (forgetting real english words that are embedded like 'low' 'el' 'hell')

Incidentally get the following results (reformatted):

el,ell,ello,elloh,ellohi,
he,hel,hell,hello,helloh,hellohi,hi,
ld,ll,llo,lloh,llohi,lo,loh,lohi,
oh,ohi,or,orl,orld,
rl,rld,wo,wor,worl,world
[download]

I have a feeling there isn't really a way to do what the OP wants to do. Its not really prefix matching, nor suffix matching....

To the OP what should happen here if said 7 words? 'hellohiothellobrakerakerashash'

Yves
--
You are not ready to use symrefs unless you already know why they are bad. -- tadmc (CLPM)

Update minor bugfixes and challenge to Op

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