Notifications are not localised properly. Looks like the language of a notification depends on the language setting of the user who caused the notification. See: https://dl.dropboxusercontent.com/u/391374/WhatsApp%20Image%202016-09-05%20at%2011.52.54.jpeg
Yup — this is a limitation of our current internationalization infrastructure. We’d love to improve it some day but it’s not presently on the road map. We’ll update this post when that changes. Sorry for any inconvenience caused in the meanwhile!