Cloned from launchpad blueprint https://blueprints.launchpad.net/neutron/+spec/user-locale-api.

Description:

Currently, error messages coming back from the API are translated using the same locale as the system the Neutron API is running on. Ideally, we would like to have the messages translated to the request senders locale, which we can support using the HTTP Accept-Language header to determine before sending back the translated response. Alternatively, there is the possibility of using the tenant/user data from Keystone to store a preferred locale.

There is a similar blueprint for Nova that can be used to track the implementation work there: 
https://blueprints.launchpad.net/nova/+spec/user-locale-api

Specification URL (additional information):

None