Please note that even a single HTML element or a space will be considered as content in a language tab. Therefore please make sure if anything has been entered by using Tools > Source code in the language tabs whenever you get an empty page although you have entered text into the Standard tab.
If the tab name is displayed in bold (e. g. EN instead of EN), this means that the tab contains content (except for the standard tab – which is always bold).
Another reason might be a missing or incorrect link in the page structure.
You can find more information about this in our manual: Writing Article Contents