Demonstrative pronouns belong to an ancient class of words that goes back to two Indo-European roots – seand to. In OE the sound [Ө] started to dominate over the sound [s] due to the pressure of the system (the forms with the sound [Ө] were more numerous (see the table below)).
Demonstrative pronouns in OE changed in Gender, Number, Case:
| Pronoun in ModE | Demonstrative Pronouns in OE | ||||
| Case | Masculine, Sg | Feminine, Sg | Neuter, Sg | Plural | |
| that | Nom | se* | sēo* | þæt* | þa |
| Gen | þes | þǽre | þæs | þara | |
| Dat | þæm | þǽre | þæm | þam | |
| Acc | þone | þā | þæt | þa | |
| Instr | þý* | þǽre | þý | þam | |
| this | Nom | þes | þeos | þis* | þās |
| Gen | þisses | þisse | þisses | þissa | |
| Dat | þissum | þisse | þissum | þissum | |
| Acc | þisne | þās | þis | þās | |
| Instr | þissum | þisse | þys | þissum |
In MEthe Case system disappeared due to the fact that there were some homonymous forms (see the table above: e.g. þǽre – F, Sg, Gen; F, Sg, Dat; F, Sg, Instr; þa – Pl, Nom; Pl, Acc; þisse – F, Sg, Gen; F, Sg, Dat) and due to phonetic reduction.
In NEthe Gender was lost due to the fact that there were some homonymous forms (see the table above: e.g. þes/þæs – M, Sg, Gen; N, Sg, Gen; þæm – M, Sg, Dat; N, Sg, Dat; þissum – M, Sg, Dat; N, Sg, Dat) and the following changes happened to the pronouns marked with * in the table above:
· se (M, Sg, Nom) – turned into the definite article “the” (discussed more particularly in the point “Rise of Articles” below);
· sēo (F, Sg, Nom) – turned into the personal pronoun “she” (discussed more particularly in the point “Personal Pronouns” (changes in the 3rd person) below);
· þæt (N, Sg, Nom) – remained as the unchangeable demonstrative pronoun “that”;
· þis (N, Sg, Nom) – remained as the unchangeable demonstrative pronoun “this”;
· þý (M, Sg, Instr) – in OE was used in the comparative constructions like “the sooner…the better” but in NE was not distinguished any more phonetically and merged with the unchangeable form of the definite article “the”.
The only category that was left in the demonstrative pronouns was the Number (e.g. ModE this – these, that – those).