"Mädchen trinken Milch."
How can anybody know when they Madchen means girl and when Madchen means girls?
Does this mean "Girls drink milk", ie in general, or is it supposed to be more specific?
Yep. If it was talking about a particular group of girls, the sentence would be Die Maedchen trinken Milch (The girls drink milk)
Why doesn't this also mean "Girls are drinking milk" or "Girls drinking milk"?
why there is no article before 'Madchen' and why does it means only plural and not singular girl?