The changes known as the loss of inflexions in English (11th- 15th centuries, included) were prompted with the introduction of a new mode of thinking. The mode of thinking, for the Anglo-Saxons, was a dynamic way of conceiving of things. Things were considered events happening. With the contacts of Anglo-Saxons with, first, the Romano-British; second, the introduction of Christianity; and finally with the Norman invasion, their dynamic way of thinking was confronted with the static conception of things coming from the (...) Mediterranean. The history of English from the 11th to the 15th century meant the introduction, confrontation and adoption of a new mental conception of things, the static way of conceiving of things, both modes of thinking defining the language today. (shrink)

Language exists because human subjects define themselves in the circumstance they are in. This is possible because they are able to know, not directly through their senses only, but adding something new to the construct they create in their conscience. The main thing they add to the construct created is categories, something invented or fabricated by the human subject at the moment of speaking.