$words = array( 'MVW',
                'MWAH',
                'MWAH',
                'MYW',
                'MW',
                'MY9AH',
                'MYQAH',
                'MYQAH',
                'MY9AH',
                'MYQAH',
                'MYQAH',
                'MWAH',
                'MYQAH',
                'MYSWI',
                'MYQAH',
                'MYQAH',
                'MW',
                'MW',
                'MW',
                'MW');

1. char is: M - occurred 20 times as 1. character in words.
    2. char is: Y - 11 times.
    3. char is: Q - 7 times.
    4. char is: A - 10 times.
    5. char is: H - 9 times.

<?php

$words = array( 'MVW',
                'MWAH',
                'MWAH',
                'MYW',
                'MW',
                'MY9AH',
                'MYQAH',
                'MYQAH',
                'MY9AH',
                'MYQAH',
                'MYQAH',
                'MWAH',
                'MYQAH',
                'MYSWI',
                'MYQAH',
                'MYQAH',
                'MW',
                'MW',
                'MW',
                'MW');


$newarray = array();
$cc2 = 0;
$cc3 = 0;
$cc4 = 0;
$cc5 = 0;
$cc6 = 0;

foreach($words as $run) {

    if (isset($run['1']) && !isset($run['2'])) {
        $newarray[] = array($run['0'],$run['1']);
        $cc2++;
    }

    if (isset($run['2']) && !isset($run['3'])) {
        $newarray[] = array($run['0'],$run['1'],$run['2']);
        $cc3++;
    }

    if (isset($run['3']) && !isset($run['4'])) {
        $newarray[] = array($run['0'],$run['1'],$run['2'],$run['3']);
        $cc4++;
    }

    if (isset($run['4']) && !isset($run['5'])) {
        $newarray[] = array($run['0'],$run['1'],$run['2'],$run['3'],$run['4']);
        $cc5++;
    }

    if (isset($run['5']) && !isset($run['6'])) {
        $newarray[] = array($run['0'],$run['1'],$run['2'],$run['3'],$run['4'],$run['5']);
        $cc6++;
    }

}

echo "Length / Found words<br>n";
echo "2 chars / $cc2<br>n";
echo "3 chars / $cc3<br>n";
echo "4 chars / $cc4<br>n";
echo "5 chars / $cc5<br>n";
echo "6 chars / $cc6<br>n";

echo "<pre>";
var_dump($newarray);
echo "</pre>";
?>

Length / Found words
2 chars / 5
3 chars / 2
4 chars / 3
5 chars / 10
6 chars / 0
array(20) {
  [0]=>
  array(3) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "V"
    [2]=>
    string(1) "W"
  }
  [1]=>
  array(4) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "W"
    [2]=>
    string(1) "A"
    [3]=>
    string(1) "H"
  }
  [2]=>
  array(4) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "W"
    [2]=>
    string(1) "A"
    [3]=>
    string(1) "H"
  }
  [3]=>
  array(3) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "Y"
    [2]=>
    string(1) "W"
  }
  [4]=>
  array(2) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "W"
  }
  [5]=>
  array(5) {
    [0]=>
    string(1) "M"
    [1]=>
    string(1) "Y"
    [2]=>
    string(1) "9"
    [3]=>
    string(1) "A"
    [4]=>
    string(1) "H"
  }
  [6]=>
  array(5) {
    [0]=>
    string(1) "M"
    .........