Etymology
The origin of this N English demonstrative pronoun and adj. is unclear and no single explanation has been found entirely satisfactory. (1)
MED prefers to derive it from ON, cp. OIcel
þeir ‘they’, but notes others have explained it by analogical processes.
OED notes the shortcomings of both approaches: ON derivation would not explain the vocalism of the ME form and the fact that this word occurs in texts alongside
þay (pron.) in its original sense would be very curious.
OED's objection that the retention of inflectional
-r is otherwise unexemplified can, however, be dismissed. The N distribution of the word, which is circumstantial evidence, is perhaps the best reason to look for ON input. (2) Though entirely speculative, the analogical explanations, e.g.
his:
hire,
this:
thire (Dobson) and
es ere:
this thire (see Bazell 1962) are perhaps more plausible. The objection that they are unparalleled remains, though, and also applies to the suggestion (3) that
þire represents a combination of
þe hēr.
PGmc Ancestor
(1) *þai + z
Proposed ON Etymon (OIcel representative)
(1) þeir ‘they’
(ONP þeir (CV))
Other Scandinavian Reflexes
Early runic þaiʀ, þeiʀ, etc., Far teir, Icel þeir, Norw dei, Dan de, OSw þē(r), Sw de
OE Cognate
(1) þā ‘those’
Phonological and morphological markers
Summary category
DD1c