The core module Text::Wrap seems to do what you want:

use strict;
use warnings;
use Text::Wrap;

$Text::Wrap::columns = 11;
my $list = 'abcd efghi jkl mnop qrst uvwxyz';
print wrap('', '', $list);
print "\n";

__END__
abcd efghi
jkl mnop
qrst
uvwxyz
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