It is not currently possible to translate the author or tag URLs, but it will very soon be possible to change them. We’re intending to make this possible via a routes.yaml file that lives in content/settings.
This feature is currently a work in progress.
@Juan the config.channels.json concept has been superceded by the Dynamic Routing spec. That config file will be going away in one of the next releases in favour of this new file, which will be considered a “beta” feature i.e. working but still subject to breaking changes.