What am I talking about? What are .mo and .po files?
I’l explain that based on a problem that needs a solution. Lets say we have a website written in english. On it we use some generic strings (e.g. “Last posts”, “Comments”, “Login”, “Archive for cathegory”, etc.) that we want to translate into specific language(s) on demand (e.g. click on specific button on the page). In case our website visitor speaks English, we want all this generic strings to be displayed in English. In case he speaks Slovenian, we’d like to have a a trigger (such as flag icon or button) on the page that can trigger translation commands so that all generic strings are shown in Slovenian language.