Latin Has a Variety of Demonstratives
The term "demonstratives" means that words so designated point out people or things, since the Latin de + monstro = 'I point out.' Demonstratives can be used in two ways:
- with nouns as adjectives or
- as stand-alone forms -- pronouns.
The nominative, singular, masculine for the four main demonstrative pronouns are:
- Ille (that),
- Hic (this),
- Iste (that), and
- Is (this, that) [Determinatives].
Is, Ea, Id is called the weak demonstrative (or weakly deictic [from the Greek δεῖξις 'demonstration, reference']) because the force of its pointing out 'this' and 'that' is weaker that that of ille or hic.
While any one of these demonstratives could be used for the third personal pronoun, is ( ea for the feminine; id for the neuter) is the one that serves as the third person pronoun in paradigms of the Latin personal pronouns (I, you, he/she/it/, we, you, they). Because of this special use, the demonstrative pronoun is, ea, id warrants being singled out.
Latin Doesn't Require a Stated Noun or Pronoun, Demonstrative or Otherwise
Before going into the use of the demonstrative as pronoun, remember that in Latin the verb's ending includes information about who is doing the action, so often you don't need a pronoun. Here's an example:
'He was walking.'
Economy of expression dictates using ambulabat for 'he is walking' unless there is a reason to specify the pronoun. Perhaps you're pointing to someone across the street who is standing still now. Then you might say:
'That (man) was wallking.'
Examples of Is As Demonstrative Adjective and Pronoun
Quis est is vir?
'Who is this man?'
shows the adjectival use of is.
Once the man (vir) has been identified, you can use the demonstrative pronoun is to refer to him. This referring back is called "anaphoric." (In practice, the reference could be one that is expected to come soon, instead of one that has already been made.) Notice I say "him" instead of "this" because it makes better sense in English. You could also use other demonstratives, like hic 'this man (here)' or ille 'that man (there).'
Using is (in this case, the accusative form eum) as a substantive or pronoun is possible once you've identified the man in our example: Eum non video. 'I don't see him.'
Here's another example where the interrogative pronoun quis encompasses the idea of a group of people, so the demonstrative (iis) can refer back to it, even though Latin word order tends to put the demonstrative before the word to which it refers [Source: The Emergence and Development of SVO Patterning in Latin and French: Diachronic and Psycholinguistic Perspectives, by Brigitte L. M. Bauer]:
Id iis eripi quis pati posset? 'Who could have permitted this to be taken from them?' [Source: The writing of narrative Latin.]
If there is not a noun the demonstrative is (and all its other forms) could modify in the passage you're translating, then you can assume it is a pronoun and you should translate it as a third personal pronoun. If there is a noun that it could modify, you have to decide whether or not it's serving as an adjective with that noun.
Adjectival: These girls are beautiful: Eae/Hae puellae pulchrae sunt. Pronomial: Their mother is kind: Mater earum benigna est.
'Is, Ea, Id' Paradigm
This, that (weak), he, she, it
Is Ea Id