title: Quickly count how many words a letter shows up in
body: <p>I have an array of words, I need to figure out how many words each letter shows up in. The number of times per word doesn't matter, only the number of words.</p>
  
  <p>I only need to check on <code>a-z</code>, but since the array of words can be quite large (over 100,000) at a time, 26 iterations through the whole loop will take far too long for this.</p>
  
  <p>What's a quicker way to check this? 260,000 loops is far too many for this.</p>