title: PHP Regex - Must contain at least any 2 letters in UTF-8
body: <p>Right now, i'm trying to create a PHP Regular Expression with these following conditions:</p>
  
  <ul>
  <li>Accepts all UTF-8 characters</li>
  <li>Space between words are allowed, how only 1 space and not multiple.</li>
  <li>Allow all symbols for example: !#$%^&amp;*()_-={}[] except: "@"</li>
  <li>No trailing spaces after or before the string.</li>
  <li>Range should be 2-16 characters including spaces</li>
  <li>And must contain at least 2 letter characters in the string.</li>
  </ul>
  
  <p>Here is the Regex I have drawn up so far:</p>
  
  <p><code>/^(?=.{2,16}$)[^@\s]+(?:\h[^@\s]+)*$/um</code></p>
  
  <p>So far this does all of the following except that it doesn't meet the last condition which is that it must contain at least 2 letters. For example:</p>
  
  <p><code>"..He" //should be true</code></p>
  
  <p><code>"He$*" //should be true</code></p>
  
  <p><code>".." //should be false</code></p>
  
  <p><code>"*%" //should be false</code></p>
  
  <p><code>"!#$%^&amp;*()" //should be false since there is no letters</code></p>
  
  <p><code>"$$tonyMoney™" //should be true</code></p>
  
  <p><code>"أنا أحب جا™" //should be true</code></p>
  
  <p><code>"To" //should be true</code></p>
  
  <p>Any help is appreciated! Thank you!</p>