my @words;

while ($content =~ /($word)/g) {
   push(@words, $1);
}

my @words_bi;
my @words_tri;

foreach (0..$#words) {
   next if $_ < 1;
   push(@words_bi,  [ @words[$_-1 .. $_] ] );

   next if $_ < 2;
   push(@words_tri, [ @words[$_-2 .. $_] ] );
}