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comparative case

n. (context grammar English) A case used to mark a likeness to something, or that two things have the same quantity of something. It corresponds roughly to the English adverb "like#Adverb". Languages that use the comparative case include Mari, Nivkh, and Chechen.

Wikipedia
Comparative case

The comparative case ( abbreviated ) is a grammatical case used in the Mari language to mark a likeness to something. It is marked with the suffix -ла ('-la') For example, if something were to taste like fish (кол - 'kol'), the form used would be колла - 'kolla').

It is also used in regard to languages, when denoting the language a person is speaking, writing, or hearing. Then, however, the accentuation varies slightly from the standard case. Usually, the suffix is not stressed. When it is used with languages, however, it is stressed.

It is not to be confused with the comparative degree, a much more widely used paradigm used to signify heightening of adjectives and adverbs.