title: How to specify browser language in Puppeteer
body: <p>I would like to launch a Google Chrome browser with language Spanish <code>es</code> using Puppeteer.</p>
  
  <p>I've tried <code>puppeteer.launch(args:['--lang=es',...],...)</code> but it didn't work.</p>
  
  <p>I've tried passing the environment variable <code>LANGUAGE=es mocha puppeteer-test.js</code> but it didn't work.</p>
  
  <p>I've tried using the <code>userDataDir</code> option and passing a folder with a <code>Preferences</code> file a <code>{ "intl": { "accept_languages": "es" } }</code> but the browser Settings - Languages still don't show Spanish and neither does <code>window.navigator.languages</code> neither <code>window.navigator.language</code></p>
  
  <p>I'm using<br>
  Puppeteer 0.11.0<br>
  Node 8.4.0<br>
  NPM 5.2.0<br>
  macOS El Capitan 10.11.6<br>
  MacBook Pro Retina, 15-inch, Mid 2015<br></p>