Later, on the same day I called in to report the issue, the update disappeared and I received a new, normal looking one. Not sure if it's the same for everyone else, but I think the issue was resolved. Good Luck!
This issue was fixed sometime early morning on July 16 EDT. Message changed back to English and it installed fine on my son's Nexus 7. Weirdly I didn't have the problem with the update message in the wrong language on any other devices. Nexus 5X and 6P updated like usual