title: Amazon Cloudsearch : Filter if exists
body: <p>I have an amazon cloudsearch domain. The aim is to filter if the field 'language' exists.
  Not all objects have a language, and I want to have the ones which do have a language filtered, but the ones that do not have any language to also be returned.</p>
  
  <p>I want to filter with 
  ( or language:'en' language:null )</p>
  
  <p>However null cannot be passed within a string.</p>
  
  <p>Is this possible? If so how would it be done.</p>