Historically, though, the morphology is more complex.
Old English had a single third-person pronoun - from the Proto-Germanic demonstrative base *khi-, from PIE *ko- "this" - which had a plural and three genders in the singular. The modern pronoun it developed out of the neuter, singular. The older pronoun had the following forms:
|Dative||him||him||hire||him / heom|
|Genitive||his||his||hire||hira / heora|
In the 12th century, it started to separate and appear without an h. Around the same time, one case was lost, and distinct pronouns started to develop, so that by the 15th century and Middle English, the forms of it were as follows:
The hit form continued well into the 16th century but had disappeared before the 17th in formal written English.:147 Genitive its appeared in the later 16th century and had taken over by the middle of the 17th, by which time it had its modern form.:148
It is considered to be neuter or impersonal / non-personal in gender. In Old English, (h)it was the neuter nominative and accusative form of h?. But by the 17th century, the old gender system, which marked gender on common nouns and adjectives, as well as pronouns, had disappeared, leaving only pronoun marking. At the same time, a new relative pronoun system was developing that eventually split between personal relative who and impersonal relative which.:1048 As a result some scholars consider it to belong to the impersonal gender, along with relative which and interrogative what.
In Old English, a subject was not required in the way it is today. As the subject requirement developed, there was a need for something to fill it with verbs taking zero arguments. Weather verbs such as rain or thunder were of this type, and, as the following example:208 shows, dummy it often took on this role.
Gif on sæternesdæg geðunrað, þaet tacnað demena and gerefena cwealm
If on saturn's-day thunders, that portends judges' and sheriffs' death
If it thunders on Saturday, that portends the deaths of judges and sheriffs
But these were not the only such verbs. Most of the verbs used without a subject or with the dummy it belong to one of the following semantic groups:
- (a) Events or happenings (chance, happen, befall, etc.)
- (b) Seeming or appearance (seem, think, become, etc.)
- (c) Sufficiency or lack (lack, need, suffice, etc.)
- (d) Mental processes or states (like, list, grieve, please, repent, rue, etc.):250
And examples still remain, such as the expression suffice it to say.
We see the same use of dummy it in cleft constructions, such as it's obvious that you were there.
It's referents are typically impersonal physical objects, but also include abstract concepts, situations, actions, characteristics, and almost any other concept or being, including, occasionally, humans, as in the following example from Lewis Carroll:
The baby grunted again, and Alice looked very anxiously into its face to see what was the matter with it.
QUÆRE--whether we may not, nay ought not, to use a neutral pronoun, relative or representative, to the word "Person," where it hath been used in the sense of homo, mensch,[a] or noun of the common gender, in order to avoid particularising man or woman, or in order to express either sex indifferently? If this be incorrect in syntax, the whole use of the word Person is lost in a number of instances, or only retained by some stiff and strange position of the words, as--"not letting the person be aware wherein offense has been given"--instead of--"wherein he or she has offended." In my [judgment] both the specific intention and general etymon of "Person" in such sentences fully authorise the use of it and which instead of he, she, him, her, who, whom.
The children's author E. Nesbit consistently wrote in this manner, often of mixed groups of children: "Everyone got its legs kicked or its feet trodden on in the scramble to get out of the carriage." This usage (in all capital letters, as if an acronym) also occurs in District of Columbia police reports.
According to the OED, the following pronunciations are used: