Perl's 2d arrays are actually arrays of array references. Each array reference, when dereferenced will contain 38 elements. perllol has a full description of manipulating "lists of lists". And perlreftut as well as perlref will get you started on dealing with references.

You might inspect the output like this:

my @output = sortList( @flatlist );
foreach my $array_ref ( @output ) {
    print "@{$array_ref}\n";
}
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Another way to write your "38 at a time" code is to use List::MoreUtils natatime function, like this:

use strict;
use warnings;
use List::MoreUtils qw( natatime );

my @biglist = (1 .. 1444);

foreach my $array_ref ( sortList( @biglist ) ) {
    print "@{$array_ref}\n";
}

sub sortList {
    my $it = natatime 38, @_;
    my @output;
    while ( my @sublist = $it->() ) {
        push @output, \@sublist;
    }
    return @output;
}
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