She/her

That is unusual for the commonest words in a language, which tend to be the best documented. The American Dialect Society picked she as its word of the millennium in 1999, and the word it picked has no agreed etymology.

Which forms she takes in modern English

Wikipedia counts four shapes carrying five word forms. She is the nominative, her does duty as both the accusative and the dependent genitive, hers is the independent genitive, and herself is the reflexive. That is why the object and the possessive determiner below hold the same word where other sets hold two.

The article's own examples run through every position: She's there as subject, I saw her as object, The only person there was her as predicative complement, This is her book as dependent determiner, This is hers as independent, She did it herself as adjunct, and, rarely, The she goat was missing as a modifier inside a noun phrase. Merriam-Webster adds the noun, glossed as a female person or animal and usually found in combination: she-cat, she-cousin. The article also collects the dependents, which pronouns rarely take: a relative clause in she who arrives late, an adjective phrase in the real her, an adverb phrase in not even her, and the flat determiner use in an exchange where somebody answers that they are that she.

Why nobody agrees where she came from

Old English had a single third-person pronoun with three genders in the singular, and the feminine nominative was hēo. Wikipedia puts the point sharply: historically she was contained inside he, and the neuter and the feminine split off from it during Middle English, which is why English now has exactly one feminine pronoun where it once had a gender of a shared word. Her comes from that paradigm without difficulty, out of the feminine singular dative and genitive hire. The nominative is the problem.

The traditional explanation derives she not from hēo but from sēo, a demonstrative meaning that one, used with a feminine noun. It has a good parallel: the feminine pronouns of the other Germanic languages, Gothic si and Old High German siu, came from demonstratives in exactly that way. It also has a hole in it, which Gorrie states plainly. Sēo had largely dropped out of use before the new forms of she appeared, leaving a chronological gap nobody has bridged.

The competing account is the one the philologist A. H. Smith called the Shetland Theory, because it assumes the sound change that turned Old Norse Hjaltland into Shetland and Hjalpandisey into Shapinsay. On this reading she is hēo all along: the stress shifts off the first vowel, giving something like hyo, and the resulting hy hardens to sh. Wikipedia notes the objection immediately. The change yields a form with an o in it, so any solution that gets the sh from hēo still has to explain the vowel of the modern word, probably by an analogical transfer of the e of he. The article's verdict on the whole field is one sentence: none of this is entirely plausible.

How hoo and scho lost out to sche

The regular development of Old English ēo is the vowel in bee, glee and tree, all of them from bēo, glēo and trēo. Applied to hēo it gives hee, which would have been indistinguishable in speech from he. A minority of ēo words went the other way instead, as ċēosan became choose rather than cheese, and applied to hēo that route gives hoo, which is still spoken in parts of Lancashire, south-western Yorkshire and the north-west Midlands.

Colin Gorrie opens his account with the consequence, staged as an argument in a York marketplace in the thirteenth century: a Yorkshire wool merchant says scho of his wife, a London cloth merchant says hoo, neither can follow the other, and the East Midlands scrivener standing by would write sche. Only the scrivener's form survived.

By the twelfth century, English had sche, scho, cho, she, heo and ho all in use for the same word. Gorrie attributes the profusion to the period rather than the pronoun: through most of Middle English the language of government and high culture was French, so English was under none of the pressures towards standardisation that a chancery language faces, and its dialects diverged accordingly.

The northern scho spread south and displaced the southern hee and hoo forms by the fourteenth century. The East Midlands form sche, which is the ancestor of the modern spelling, looks like the beginning of the northern word attached to the end of the southern one. By the fifteenth century the paradigm had settled into the forms still in use, the reflexive included: hire self had become herself in early Middle English.

Where she stands in for an unspecified person

Merriam-Webster's third sense for the pronoun is she used as an alternative to he for a person of unspecified gender, illustrated from D. J. Callahan on allowing anyone to do whatever she wants. Wikipedia records the same use as occasional, and gives the shape of it: a sentence about somebody in trouble, or about whichever parent wishes to discuss something, taking her for a referent who is not known to be a woman.

The dictionary also carries the two spliced forms as headwords in their own right. S/he is glossed as she or he, used in writing as a pronoun of common gender, and he/she gets an identical gloss. Both entries treat the compound as a written device rather than a spoken one, which is what the punctuation in them is doing.

Why ships and countries are called she

The convention for ships is old enough to survive in ordinary journalism: Wikipedia's example is the SS Edmund Fitzgerald, launched in 1958, of which it is written that she was then the largest ship on the Great Lakes of North America. The habit extends to other inanimate objects by the same anthropomorphising route, as with the car named Eleanor in the 2000 film Gone in 60 Seconds.

Countries take she under one restriction. A country as a political entity can be she, as in a sentence about Canada finding her place in the world during the Second World War. The same country as a piece of geography cannot, which is why a sentence about the prairies and the great lakes will not take the pronoun. Deities are a separate case, where She appears with a reverential capital, whether of a particular goddess or of a monotheistic God regarded as female.

Many English style guides discourage all of this, and Wikipedia records that such use may be considered dated or sexist. It does not say by whom, and no source traced for this entry dates the turn.

Who uses she besides women and girls

Heckin' Unicorn's glossary entry, updated in September 2021, describes she, her and hers as a set of gender-specific pronouns typically used for women and girls, and adds that some Non-binary people use it, as do some Genderfluid and Genderqueer people. The same entry separates two things that are often run together: a pronoun set is not a statement about sexual orientation, which is why the practice of stating pronouns in workplaces and on profiles is not confined to LGBTQ people.

That leaves she doing three jobs at once in current English. It is the ordinary pronoun for a Woman, it is the set some people outside that category state for themselves, and it is the residual pronoun for ships, countries and a small stock of personified objects.