You might want to convert the strings to soundex and then compare them:

$longest  = soundex of longer string
$shortest = soundex of shorter string

if ($longest =~ /$shortest/) {
  ...
}
[download]

as a quick check. Then do the same for un-soundex versions. if not exact, perhaps try exact word s/// - if no word chars left, assume it's the same quote (or subset of).

cLive ;-)