Change language of Drupal nodes in bulk

On websites with only one non-English language, there are often nodes left in English. This can cause problems: the wrong language is shown on the front-end of the node and sometimes clean urls don't work. 

Luckily, there is a solution to bulk convert all nodes to the correct languages. This method uses VBO and Views: https://drupal.stackexchange.com/a/55296.