U kinu sjedimo jedan pokraj drugoga.

Because after u meaning in, Croatian normally uses the locative case when you are talking about location.

• kino = nominative
• u kinu = locative, meaning in the cinema

So:

• Idemo u kino. = We are going to the cinema. → movement, so accusative
• U kinu sjedimo... = We are sitting in the cinema. → location, so locative

That location-vs-movement contrast is very important with u.

Because kino is a neuter noun, and in the locative singular its ending changes.

A short declension sketch:

• kino = nominative
• kina = genitive
• kinu = dative/locative
• kinom = instrumental

So u kinu is just the regular locative form of kino.

Sjedimo means we sit / we are sitting.

It comes from the verb sjediti = to sit, to be sitting.

Form breakdown:

• sjed- = verb stem
• -imo = we ending in the present tense

So sjedimo = we are sitting.

In context, English will usually translate it as we are sitting rather than the more general we sit.

Because Croatian distinguishes between:

• sjediti = to be sitting / to sit in a continuous state
• sjesti = to sit down / to take a seat

So:

• U kinu sjedimo jedan pokraj drugoga. = We are sitting next to each other in the cinema.
• Sjednemo u kinu... or sjedamo u kinu... would suggest the action of sitting down, not the state of already being seated.

This is an aspect/state distinction that English often does not mark as clearly.

Literally, it is something like:

• jedan = one
• pokraj = beside / next to
• drugoga = the other

So the phrase literally looks like one beside the other.

In natural English, that becomes next to each other.

Croatian often expresses reciprocity this way instead of using a single word equivalent to English each other.

Because pokraj takes the genitive case.

The basic form is:

• drugi = other, second
• after pokraj it becomes drugoga (genitive singular masculine/neuter)

So:

• pokraj drugoga = next to the other one

This is not random: many Croatian prepositions require a specific case, and pokraj is one of the prepositions that uses the genitive.

Because jedan ... drugoga is a set expression used to mean each other.

It is not there to count people literally. It helps build the reciprocal meaning:

• jedan drugoga
• jedan pokraj drugoga
• jedan s drugim

These all involve the idea of one ... the other, which together gives the sense each other.

So even though the subject is already we, the phrase is still needed to show the relationship between the people.

Because Croatian often uses the singular pattern in reciprocal expressions even when the overall meaning is plural.

So jedan pokraj drugoga is the normal idiomatic way to say next to each other.

A learner may expect a plural form because English thinks of we as plural, but Croatian commonly builds this kind of meaning through a one ... the other structure in the singular.

Yes. That would also be correct.

Croatian word order is fairly flexible, and both versions are natural:

• U kinu sjedimo jedan pokraj drugoga.
• Sjedimo u kinu jedan pokraj drugoga.

Putting U kinu first gives it a bit more topical emphasis, like:

• In the cinema, we sit next to each other.

So the first position often highlights the setting or context.

Because Croatian usually does not need subject pronouns unless you want emphasis or contrast.

The ending -imo in sjedimo already tells you the subject is we.

So:

• sjedimo = we sit / we are sitting

You could say Mi sjedimo..., but that would sound more emphatic, like:

• We are sitting next to each other.

Without emphasis, leaving out mi is completely normal.

Often yes, but its basic sense is more like beside, by, or alongside.

In this sentence, jedan pokraj drugoga is very naturally translated as next to each other.

Other similar Croatian words include:

• kraj = by, beside
• uz = next to, alongside
• pored = beside, next to

In many contexts these can overlap, but pokraj works very well here.

Yes, it could.

The form in your sentence, jedan pokraj drugoga, is masculine and can also function as the default for a mixed group.

If the speakers were all female, you would normally expect:

• U kinu sjedimo jedna pokraj druge.

So the pattern changes for gender:

• masculine/mixed: jedan pokraj drugoga
• feminine: jedna pokraj druge

This is a very common feature in Croatian: adjectives and related words agree in gender and case.

It can be either, depending on context.

Sjedimo in the present tense can mean:

• we are sitting right now, or
• we sit as a usual arrangement

So:

• in a story about what is happening now: We’re sitting next to each other in the cinema.
• in a more general statement: At the cinema, we sit next to each other.

Croatian present tense often leaves that distinction to context, just as English sometimes does.