I'm not sure about the application, but it might be advisable to at least put in some '\b's to prevent unfortunate collisions that would render some names as "Mikestone", or "Moeseph".

Here is a slight modification of japhy's (or merlyn's, you decide) code:

  $keys     = join '|', map "\\b\Q$_\E\\b", keys %sub_hash;
  $keys_REx = qr/$keys/;
  $string   =~ s/($keys_REx)/$sub_hash{$1}/g;
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