Adjectives, those troublesome things (6)

Now, last time I explained that the short-form singular accusative case of Russian adjectives remains in modern Russian in the fixed expression на бóсу нóгу ('barefoot'), but it is no surprise that some might wonder if other case forms existed as well, given that an accusative form exists (or existed).
Actually, that is exactly right; in Old Russian (the older Russian used roughly before the 15th century), those inflected forms were used in full.
This means that these short forms, like the long forms, functioned as a type of adjective modifying nouns.
Here, let's decline the short form of 'good wife' in that so-called Old Russian.
Nominative: добра жена
Genitive: добры жены
Dative: добрѢ женѢ
Accusative: добру жену
Instrumental: доброю женою
Prepositional: добрѢ женѢ
Vocative: добра жено!

Unlike modern Russian, there is one additional case form.
That is, there is a vocative case (a form used for addressing someone, like 'Good wife!').
This is a case form that still remains in modern Slavic languages like Czech and Polish.
Also, the Ѣ that appears in the dative and prepositional cases is a letter called 'yat', which was used in Russian until the orthography reform of 1918, but is not used today.
There are various theories about how it was pronounced, but for convenience, it is fine to pronounce it as [je].
Looking at the accusative form добру жену, we can confirm the exact same ending change as in the aforementioned (на) бóсу нóгу.

In other words, in the past, short forms were also used to modify nouns and were normally declined, but this gradually fell out of use, and now the only option is to use the long form, as in добрая жена.