Q: We say “her apple” and “the apple is hers,” but “his apple” and “the apple is his.” Why does “her” become “hers” while “his” doesn’t change?
A: Your question takes us back many centuries into the history of English pronouns.
As you know, “her” can be an object pronoun, as in “Give the apple to her.”
But “her” can also be used in a possessive sense, either with or without s at the end.
The possessive pronouns “her” and “hers” are used as different parts of speech.
The possessive “her” (as in “her apple”) is an adjective. But “hers” (as in “the apple is hers”) is what’s called an absolute pronoun.
Unlike “her,” the absolute pronoun “hers” doesn’t modify anything. Instead, “hers” stands for something: the thing or things belonging to her.
Is it unusual that the feminine forms of these words (“her”/“hers”) are different? Not really.
What’s odd here, as you’ll see, is that the masculine forms (“his”/“his”) are identical.
In Old English, which was spoken until about 1100, the possessive adjective “her” was written as hyre or hire.
The absolute form (“hers”), which the OED says is “used when no noun follows,” evolved later, in the 1300s.
During the Middle English period (1100-1500), “hers” was spelled hirs, hires, hyres, and even her’s, with an apostrophe to indicate possession.
The modern spelling “hers” showed up in the 1500s.
Why the final s?
Because “hers,” according to the Oxford English Dictionary, is “in form, a double possessive.” (A double possessive is a phrase that uses both “of” and an apostrophe plus s to show possession.)
The pronoun “hers” apparently came about, the OED says, “by association with the possessive case in such phrases as ‘a friend of John’s.’ ”
But “hers” isn’t unusual in having a final s that makes it resemble a double possessive.
Several other absolute pronouns evolved in similar fashion and at times have also been spelled with apostrophes (“their’s,” “our’s,” “your’s”).
Since the possessive adjective “his” already ended in s, attempts over the centuries to add another s didn’t stick.
This is why, the OED says, “the absolute his … remains identical in form with the simple or adjective possessive.”
The same thing happened with the possessive pronoun “its,” which also ends in s.
“The more recent its, also ending in s, has followed the example of his,” says the OED.
Thus we depend on the context of a sentence to determine whether the “his” or “its” we’re reading is an adjective or an absolute pronoun.
That’s generally not much of a problem.
A “his” or an “its” that modifies a noun (as in “his apple” or “its apple”), is a possessive adjective.
Otherwise (as in “the apple is his” or “the apple is its”), you have an absolute pronoun.
If you’d like to read more, we touched on this subject a couple of months ago in a blog posting about the double possessive.
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