I'm not unsure that it isn't impossible to avoid not including more negations without having to avoid a lack of not trying.

Clarity itself to a logician, certainly, but — on the offchance that some following along at home might need a little help — let Perl elucidate:

#! perl
use strict;
use warnings;

my $str1 =  "I'm not unsure that it isn't impossible to " .
            "avoid not including more negations without " .
            "having to avoid a lack of not trying.";
my $str2 =  $str1;
my %negs = ("not un"                  => "",
            "it isn't im"             => "it's ",
            "avoid not including"     => "include",
            "without having to avoid" => "by",
            "a lack of not"           => "");

# Collapse double negatives
while (my ($key, $value) = each %negs)
{
    $str2 =~ s/$key/$value/g;
}

# Remove extra spaces
$str2 =~ s/\s+/ /g;

# Display the translation
print "$str1\n\n-->\n\n$str2\n";
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(Is there anything Perl can’t do?)