Previously I had been just a translator. Recently I was granted a reviewer permission for my language team and received an email notification containing this excerpt:
You are now:
Note that while I had been a translator and I also became a reviewer the message says the contrary: I had been a reviewer and I also became a translator.
In order to test please create a fake (test) user's account, give it a translator permission, then give it a reviewer permission and watch the emails. You can also play with other permission transitions.