Why do Germans have Trinkt,Trinken, and Trinkst but they all mean pretty much the same thing?
Compare it to English people having different words for the same thing. For example, brother and sibling. One of te words is more specific
They are not the same. Trinkt means "he/she/it drinks". Trinken means "to drink" and "trinkst" is in the context of "you drink". You need to focus on grammar - indeed hard work :-)