Editing Locative case (section)

===Latin===
[[Old Latin]] still had a functioning locative singular, which descended from the Proto-Indo-European form. The locative plural was already identical to the dative and ablative plural. In [[Classical Latin]], changes to the Old Latin diphthongs caused the originally-distinctive ending of the locative singular to become indistinguishable from the endings of some other cases.

{| class="wikitable"
! Declension
! Old Latin
! Classical Latin
! Merger
|-
! 1st
| -āi
| -ae
| Merged with dative/genitive.
|-
! 2nd
| -ei
| -ī
| Merged with genitive.
|-
! 3rd
| -ei, -e
| -ī, -e
| Originally like the dative, but gradually replaced with the ablative.
|-
! 4th
| colspan=2|-ī, -ibus, -ubus
| Gradually replaced with the ablative.
|}

Because the locative was already identical to the ablative (which had a "location" meaning as well) in the plural, the loss of distinction between the endings eventually caused the functions of the locative case to be absorbed by the ablative case in Classical Latin. The original locative singular ending, descended from the Old Latin form, remained in use for a few words. For first and second [[declension]], it was identical to the genitive singular form. In archaic times, the locative singular of third declension nouns was still interchangeable between ablative and dative forms, but in the Augustan Period the use of the ablative form became fixed. Therefore, both forms {{lang|la|rūrī}} and {{lang|la|rūre}} may be encountered.

The Latin locative case was only used for the names of cities, "small" islands and a few other isolated words. The Romans considered all Mediterranean islands to be small except for [[Sicily]], [[Sardinia]], [[Corsica]], [[Crete]], and [[Cyprus]]. [[Britannia]] was also considered to be a "large island". There are a few nouns that use the locative instead of a preposition: {{lang|la|domus}} becomes {{lang|la|domī}} (at home), {{lang|la|rūs}} becomes {{lang|la|rūrī}} (in the country), {{lang|la|humus}} becomes {{lang|la|humī}} (on the ground), {{lang|la|militia}} becomes {{lang|la|militiae}} (in military service, in the field), and ''focus'' becomes ''focī'' (at the hearth; at the center of the community).

The first declension locative is by far the most common, because so many Roman place names were first declension, such as {{lang|la|Roma}}, Rome, and therefore use the same form as the genitive and dative: {{lang|la|Romae}}, at Rome, and {{lang|la|Hiberniae}}, in [[Ireland (island)|Ireland]]. A few place-names were inherently plural, even though they are a single city, e.g. {{lang|la|Athēnae}}, [[Athens]] and {{lang|la|Cūmae}}, Cuma. These plural names also use the form similar to the dative and ablative: {{lang|la|Athēnīs}}, at Athens, and {{lang|la|Cūmīs}}, at Cumae. There are also a number of second declension names that could have locatives, e.g. {{lang|la|Brundisium}}, [[Brindisi]]; {{lang|la|Eborācum}}, [[York]]; with locatives {{lang|la|Brundisiī}}, at Brindisi; {{lang|la|Eborācī}}, at York. The locative cannot express being located at multiple locations; plural forms only exist because certain proper names such as {{lang|la|Athēnae}} happen to be plural. "He is at home" can be expressed by "{{lang|la|(is) domi est}}" using the locative, but "They are at their (individual and separate) homes" cannot be expressed by the locative.