When doing multi-language Voice Search before, Google would need you to change the language settings. Now, they are rolling out an update that will support multiple languages. The latest version of Google Search (version 3.6) should be up on Play Store. To activate this feature, you just need to head to the Settings menu and then select Search & Now > Voice > Languages. You can then pick up to five languages you want Google Search to understand. But Android Police points out there are still shortcomings with the update, including the lose of "Ok Google" detection. Hopefully they fix that soon.