Нам нужно спокойно объясниться, но сегодня мне не до долгого разговора.

Because Russian often uses the pattern кому-то нужно + infinitive to mean someone needs to do something.

So:

• Нам нужно объясниться = We need to talk things through / We need to clear things up

Here:

• нам = to us / for us in form, but in this structure it means we
• нужно = necessary / needed
• объясниться = to explain ourselves to each other / to clear things up

This is a very common Russian construction. Compare:

• Мне нужно уйти = I need to leave
• Тебе нужно отдохнуть = You need to rest
• Нам нужно поговорить = We need to talk

So even though English uses a subject like we, Russian often uses a dative experiencer instead.

Here нужно does not mean needed in the same way as an adjective agreeing with a noun. It is an impersonal predicative word meaning:

• it is necessary
• it is needed
• one needs to

So:

• Нам нужно спокойно объясниться literally means something like For us, it is necessary to calmly explain ourselves

In natural English, that becomes:

• We need to calmly talk things through
• We need to clear things up calmly

A useful contrast:

• Мне нужен врач = I need a doctor
  (нужен agrees with врач)
• Мне нужно уйти = I need to leave
  (нужно is impersonal and goes with an infinitive)

Объясниться is a reflexive verb, and in this context it usually means:

• to explain oneself
• to talk things through
• to clear the air
• to sort things out by talking

It often suggests that two people need to discuss a misunderstanding, tension, or problem.

Related forms:

• объяснить = to explain something
  
  • объяснить проблему = to explain the problem
• объясняться = imperfective reflexive
  
  • can mean to be explaining oneself, to talk things out, or even to declare one’s love in some contexts
• объясниться = perfective reflexive
  
  • means the conversation is viewed as a complete event: have the talk, clear things up

So in this sentence, объясниться suggests we need to have that clarifying conversation.

Because the speaker is referring to one complete conversation with a goal: to resolve something.

Perfective verbs in Russian often present an action as:

• whole
• completed
• result-oriented

So:

• Нам нужно объясниться = We need to have that talk and get things cleared up

If you used the imperfective объясняться, it could sound more like:

• the process of explaining
• repeated or ongoing explaining
• less emphasis on reaching a result

In this sentence, the speaker clearly has a specific, complete discussion in mind, so объясниться fits well.

Спокойно is an adverb meaning:

• calmly
• peacefully
• without getting emotional

It modifies объясниться, so:

• спокойно объясниться = to talk things through calmly

This tells you something about the desired tone of the conversation: not arguing, not shouting, not making it dramatic.

A similar idea in English would be:

• We need to talk this over calmly
• We need to clear things up in a calm way

Мне не до... is an idiomatic Russian expression meaning something like:

• I’m not up for...
• I’m in no mood for...
• I don’t have the time/energy for...
• This is not the moment for...

So:

• мне не до долгого разговора = I’m not up for a long conversation today
• or Today I don’t have it in me for a long talk

This expression is very common and often implies that the speaker is:

• too tired
• too busy
• emotionally not ready
• distracted by something else

Examples:

• Мне сейчас не до шуток = I’m not in the mood for jokes right now
• Ему не до сна = He’s in no state to sleep / Sleep is the last thing on his mind
• Нам сейчас не до отдыха = This isn’t the time for rest

Because the expression не до requires the genitive case.

So:

• разговор = nominative
• долгий разговор = nominative phrase
• до долгого разговора = genitive after до
• не до долгого разговора = still genitive

This is not because of English-style logic like of a long conversation; it is simply how the Russian idiom works grammatically.

Some more examples:

• не до еды = not up for food
• не до работы = not up for work
• не до серьёзных обсуждений = not up for serious discussions

For the same general reason as in the first clause: Russian often uses the dative to mark the person experiencing a state.

In мне не до долгого разговора:

• мне = to me / for me
• but naturally it means I’m not up for...

This is a very Russian way of framing things. Instead of saying I do not want or I cannot, the language often says something more like:

• For me, it is not the time/state for...

It can sound slightly softer and more situational than a direct statement like:

• Я не хочу долгого разговора = I don’t want a long conversation

The actual sentence suggests:

• maybe the speaker does understand the need to talk,
• but today they do not have the emotional space, time, or energy for a long discussion.

Russian word order is flexible, and word placement often shows emphasis or discourse flow rather than strict grammatical roles.

Here:

• но сегодня мне не до долгого разговора

puts сегодня early to highlight the time limitation:

• but today I’m not up for a long conversation

It contrasts nicely with the first clause:

• We need to talk things through calmly, but today...

So the meaning is not never, but specifically not today.

Other possible orders are possible, but they may sound slightly different in emphasis:

• Но мне сегодня не до долгого разговора
• Но не до долгого разговора мне сегодня

The given order is very natural and straightforward.

Yes. Долгого разговора means:

• a long conversation
• a lengthy talk

That softens the sentence a little. The speaker is not necessarily refusing to talk at all. They may be saying:

• we do need to discuss this,
• but I can’t handle a long, drawn-out conversation today

So the full sentence has a balanced tone:

1. Нам нужно спокойно объясниться
   = We need to clear things up calmly
2. но сегодня мне не до долгого разговора
   = but today I’m not up for a long conversation

This can imply:

• maybe a short talk is possible,
• or maybe the full conversation should happen later.

It is close, but Нам нужно спокойно объясниться is a bit more specific than just We need to talk.

We need to talk in English can mean many things. In Russian:

• Нам нужно поговорить = We need to talk
• Нам нужно спокойно объясниться = We need to calmly clear things up / explain ourselves to each other

So объясниться adds the idea of:

• clarifying misunderstandings
• resolving tension
• discussing something delicate
• making each side understood

It is often more emotionally loaded than a neutral поговорить.

Because Russian often leaves subject pronouns out when they are already clear from the structure or context.

In this sentence:

• Нам нужно... already tells you the people involved are we/us
• мне не до... already tells you the speaker means I

Adding мы or я is possible, but not necessary:

• Нам нужно спокойно объясниться...
• Мне не до долгого разговора...

This omission sounds completely natural in Russian. English usually needs an explicit subject, but Russian often does not.