Agree with choroba's post that you don't need the feature 'say' to solve your issue. But FYI, in Perl you can create your own global functions with the core module Exporter. A very naive implementation:

In MyFeatures.pm:

package MyFeatures;

use strict;
use warnings;

use Exporter qw/ import /;

our @EXPORT_OK = qw/ say /;

sub say {
    my $str = shift;
    print "$str\n";
}

1; # return true
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In your program:

#!/usr/bin/perl

use strict;
use warnings;

use MyFeatures qw/ say /;

my $str = 'Hello, world.';

say $str;
say q{Nice weather, isn't it?};

__END__
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Output:

Hello, world.
Nice weather, isn't it?
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Hope this helps.