Hi, I need some help with Perl.

I have to make a palindrome script in Perl, where it can analyze a word or sentence that is enclosed in quotations. I need it able to tell if any of the words in the sentence are palindromes. I took 1 sentence and reversed it and assigned both to 2 separate variables. I was thinking that I can compare the 2 string variables to check if they have any words that match. I understand I need to use a regular expression variables but I'm not sure which one to use. I have tried so many types and still can't get the right answer. So far I got:

#!/usr/bin/perl

$pali = shift;
$rpali = reverse $pali;

if ($pali =~ /$rpali/i)
{print "Yes!\n";}
else {print "No!\n";}


and yes this is homework but I'm not asking anyone to post the entire script. I know what to do but I just don't know what regular expression option to put. If that's still not allowed then I'm sorry. Thanks