The Noun Case System

The case system in Russian does two things. First, it marks the grammatical functions of nouns which are indicated by word order in English, that is, the subject, object and indirect object of the sentence. (This means that these nouns are free to be ordered almost anywhere in the sentence since their function is clearly indicated by their form.) Second, cases mark certain adverbial functions such as the time, manner, and means of carrying our an action, which are marked by prepositions in English, e.g. by hand, on Friday, with enthusiasm This function leads to the case system being associated with prepositions. Remember: in Russian all prepositions are associated with a case which is attached to their objects. Since only nouns can express case, this means that only nouns may be objects of prepositions.

More info: The Alpha Dictionary

What does all that mean with respect to Russian language localization?

This means that if you provide the source in a set of strings out of the context, translation may and will result in severe grammatical deflections of prepositions and noun case usage.

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