Once you know two languages of fairly dissimilar syntax and philosophy, you can learn a new language pretty quickly because of the mind-expanding effect brought

Once you know two languages of fairly dissimilar syntax and philosophy, you can learn a new language pretty quickly because of the mind-expanding effect brought about by having multiple approaches to the same problem in mind. This applies decreasingly with every language you learn, such that the usefulness of learning a new language to learning future languages is governed by 1/(n-1), where n is the new number of languages you will know after learning the new language. (Naturally applying this to one's first programming language results in a division by zero, because knowing the basic skills of programming is infinitely more useful than knowing nothing about it.)