Learn Croatian: Ne mogu razlikovati oba rukava. - I cannot distinguish both sleeves.

The noun for sleeve is rukav, which is masculine. The word for "both" has two main forms: oba for masculine and neuter nouns, and obje for feminine nouns. Since rukav is masculine, we use oba.

Why does the word for sleeve appear as rukava instead of the regular plural rukavi?

The quantifier oba (both) follows the exact same grammatical rules as the numbers two, three, and four. It requires the noun that follows it to take the "paucal" form. For masculine and neuter nouns, this form is identical to the genitive singular. The genitive singular of rukav is rukava.

What case is the phrase oba rukava in here?

It is in the accusative case, as it is the direct object of the verb razlikovati (to distinguish). For inanimate masculine nouns and all neuter nouns, the accusative form of oba is exactly the same as its nominative (dictionary) form.

In English, we usually say "I can't tell the sleeves apart." Is razlikovati the standard way to express this?

Yes! The verb razlikovati literally translates to "to distinguish" or "to differentiate". When you want to say you cannot "tell things apart" in Croatian, you use razlikovati followed by the things you are comparing as the direct object.