I understand the evolution of language to a certain degree... But how to major leaps occur? For example saying, 'I am gong to the big store' instead of 'to the store big I am going'?
Try r/linguistics, they're pretty helpful over there. This isn't really a history question.
But since you're here, The Unfolding of Language by Guy Deutscher is a very accessible book that helps to explain the mechanisms of language change.