What is a one-sentence summary of the following article?
You can change the language for the OK, Google service to both recognize and speak Arabic. You can access these settings from the Google app on your device. You can find this in the upper-left corner of the Google app. You can also swipe in from the left side of the screen. This will open the Google settings menu. This will open the voice settings for OK, Google. You'll find this option at the very top of the Voice menu. You'll have a few different voices to choose from. This voice will read back your "OK, Google" results, and will enable you to use "OK, Google" in Arabic. You'll need to stay connected to the internet in order to use "OK, Google" in Arabic, as the Arabic files are not available for offline speech recognition at the time of this writing in October 2016.

Summary:
Tap the Google app. Tap the Menu button (☰). Tap "Settings" in the Google app menu. Tap "Voice." Tap "Languages." Scroll down to find the Arabic options. Check the box for the voice you want to use.