sub namecase {
  my(@names) = @_;
  s/(\w+)/\L\u$1/g for @names;
  return @names;
}

# For example:
print join "\n" => namecase('RONNIE NUNN', 'RON OLESIAK');
print "\n";
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That works because the \L says "all lowercase", and the \u says "next letter uppercase".