The Origins of Inflections

In old english, inflections were variations of a word used to indicate some specific meaning in a sentence. The original indo european language had lots of them and even though the original proto germanic language had dropped and simplified some of them, it also relied heavily on those endings. Historically speaking, we like to use a particular word without adding a bunch of different endings or changing the middle part of the word. We just like fixed word forms. Rather than changing the form of a word, english has tended to find ways to use the ame word form to express different ideas.