title: How to replace all non-alphabetic characters with UTF-8 support in PHP
body: <p>I want to remove all non-alphabetic character from a string. The problem is that I don't know the letter range because it is UTF8 string. </p>
  
  <p>It can be ENGLISH, ՀԱՅԵՐԵՆ, ქართული, УКРАЇНСЬКИЙ, РУССКИЙ</p>
  
  <p>I usually do something like this:</p>
  
  <pre><code>$str = preg_replace('/[^a-zA-Z]/', '', $str);
  </code></pre>
  
  <p>or</p>
  
  <pre><code>$str = preg_replace('/[^\w]/u', '', $str);
  </code></pre>
  
  <p>but they both clear foreign characters.</p>
  
  <p>Any ideas?</p>