Instead of printing strings directly, write a simple wrapper:

print mt("Hello World!");
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This method searches your "dictionary" for a translation. The easiest solution is a hash:

package MyNamespace::MT::German;
...

sub mt {
   my ( $self, $phrase ) = @_;
   my %translations = ( 
      'Hello World!' => 'Hallo Welt!',
   );
   return $translations{$phrase} || $phrase;
);
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