Page History

...

Typically, Magnolia runs on two instances, the author instance and the public instance and the question of "two locales" is connected with the types of users who access a Magnolia instance.

An ordinary internet user, new or returning internet user –  – whom we can call a public user – will usually only be able to see and interact with the pages of a published web project or website. Such a user will – The user will be interacting – via the web browser – communicate – with a running public instance of Magnolia . A public user, for example and will expect that the content of each page on the site will be available in a language he can understand, ideally in his native language.

For example, a user who's native language is English and who visits and interacts with a website built with Magnolia will usually prefer if browsing the website's language were also English English language version of a website (the screenshots are from the Travel Demo):

On the other hand, an a Magnolia editor/publisher (user) or sysadmin – let's just simplify these roles to a system user – working with the author instance of Magnolia may have different locale preferences than the public user. 

...