Anyone who knows anything about Russian knows that the Russian case system is a grammatical nightmare. English, the Romance languages, and most Germanic languages in general have forsaken this beautiful yet painful system for prepositions and articles. Even in German, only the adjectives get 'cased around', and the nouns remain for the most part the same. Even Bulgarian, a Slavic relative of Russian, has since gotten rid of the heady case system.
In Russian, on the other hand, it is alive and well. And although there are prepositions, there are no articles, and there are no less than six cases: Nominative, Accusative, Genitive, Prepositional, Dative, and Instrumental. All nouns and adjectives must fall into one of these cases, as well as one of three genders and a singular or plural number.
There is an exception, however. You see, in Russian, there is no copula, that is, there is no 'is'. The verb 'to be' exists only in the past and future tenses, and only when it absolutely has to be there. So Ya vrach means 'I am a doctor'.
Because there is no 'is', when you make a statement of the form 'NOUN=ADJ.', (Like, 'she is pretty) the adjective can become a pseudo-predicate. When this happens, you can drop the case endings altogether and only decline it by gender and number, lowering your options for adjective ending from 24 to 4. Somehow that seems easier.
So instead of saying 'She is pretty' as Ona krasivaja , you can just say Ona krasiva. Or if you wanted to say 'Are you ready?', you could say the long-form adjective Ty gotovyi?, the verb Ty gotovish'sâ, or the simple short-form, zero-ending adjective Ty gotov?.
Short-form adjectives are also used as modals in Russian, that is 'can', 'should', 'could', etc. Ty dolzhna vypit' pivo means 'You need to drink a beer (fem.), and Mozhno zadat' vam vopros? means, 'May I ask you a question?' (literally, 'I am able + to ask + to you (formal) + a question?).
I just think it's interesting how things like this work in natural languages, how exceptions come about, and how languages can be so different from one another in how they express the same things.
Please forgive the lack of Cyrillic text. The computer I wrote this on seems to be a bit retarded, so I just transliterated all the Russian.