This is an interesting but, ultimately, fairly meaningless question. (Also, it isn't obviously related to the original point about English being "most rational, and sophisticated") The problem is, mainly, how do you define a word. Do you count inflections as separate words: e.g are "dog" and "dogs" one word or two. What about different meanings: "dog" the animal versus the verb "to dog"; and what about all the different meanings of that verb. And then the conjugations of the verb (dog, dogs