It's a good question, because if we really want to make sure language got changed, how can we just rely on the value of the `select` ? Because there might be chances that mozL10n API got broken somewhat so that we may not be able to `change the language`, and in this scenario, if we depends on the value to make sure languages got changed, we won't notice this failure.

And talking about `change`, I think language itself is stable enough and not be changed. For me, languages itself are just like names of countries and would not be changed without any reason. 

What do you think, Arthur ?