google/google-api-php-client — pull request #259 by Jouza (2014-07-17 13:27:35+00:00)
Title: Google Translate API - post method

https://developers.google.com/translate/v2/using_rest

You can also use POST to invoke the API if you want to send more data in a single request. The q parameter in the POST body must be less than 5K characters. To use POST, you must use the X-HTTP-Method-Override header to tell the Translate API to treat the request as a GET (use X-HTTP-Method-Override: GET).