Edward Sapir (18841939). Language: An Introduction to the Study of Speech. 1921.
morphological levelings until only certain pronouns retained distinctive subjective and objective forms.
In later medieval and in modern times there have been comparatively few apparent changes in our case system apart from the gradual replacement of thouthee (singular) and subjective yeobjective you (plural) by a single undifferentiated form you. All the while, however, the case system, such as it is (subjective-objective, really absolutive, and possessive in nouns; subjective, objective, and possessive in certain pronouns) has been steadily weakening in psychological respects. At present it is more seriously undermined than most of us realize. The possessive has little vitality except in the pronoun and in animate nouns. Theoretically we can still say the moons phases or a newspapers vogue; practically we limit ourselves pretty much to analytic locutions like the phases of the moon and the vogue of a newspaper. The drift is clearly toward the limitation of possessive forms to animate nouns. All the possessive pronominal forms except its and, in part, their and theirs, are also animate. It is significant that theirs is hardly ever used in reference to inanimate nouns, that there is some reluctance to so use their, and that its also is beginning to give way to of it. The appearance of it or the looks of it is more in the current of the language than its appearance. It is curiously significant that its young (referring to an animals cubs) is idiomatically preferable to the young of it. The form is only ostensibly neuter, in feeling it is animate; psychologically it belongs with his children, not with the pieces of it. Can it be that so common a word as its is actually beginning to be difficult? Is it too doomed to disappear? It would be rash to say that it shows signs of approaching obsolescence, but that it is steadily weakening