Nobis expedit veritatem statim dicere.

Because expedit takes the person affected in the dative case, not the nominative or accusative.

So:

• nobis = for us / to us
• nos = we or us in other sentence roles

In this sentence, nobis expedit means it is advantageous for us, it is useful for us, or more naturally it is best for us.

Latin often uses the dative with expressions that mean is beneficial, is suitable, is pleasing, and similar ideas.

Because nobis is not the grammatical subject.

The verb expedit is in the 3rd person singular because the thing that is advantageous is the action veritatem statim dicere — to tell the truth at once.

So the structure is essentially:

• [To tell the truth immediately] = the subject idea
• expedit = is advantageous / is best
• nobis = for us

In smoother English, we do not usually say To tell the truth immediately is advantageous for us, but that is close to the Latin structure.

Dicere is a present active infinitive, meaning to say or to tell.

Here it works as the core of an infinitive phrase:

• veritatem statim dicere = to tell the truth immediately

That whole phrase functions like a noun idea and serves as the thing that expedit refers to.

So the sentence is built around the idea:

• To tell the truth immediately is best for us.

Because veritatem is the direct object of dicere.

• dicere = to say / to tell
• what is being told? veritatem = the truth

So:

• veritas = truth (nominative)
• veritatem = truth as a direct object (accusative)

That is why the accusative is used.

Yes, but it is not a normal noun like Marcus or puella.

The subject idea is the infinitive phrase:

• veritatem statim dicere

Latin very often lets an infinitive or an infinitive phrase function as the subject of verbs like:

• expedit = it is advantageous
• licet = it is permitted
• oportet = it is proper / one ought
• necesse est = it is necessary

So the subject is not missing; it is just an action expressed by the infinitive.

Because Latin word order is much freer than English word order.

Statim is an adverb meaning immediately / at once, and it modifies dicere. It can often be placed in different positions without changing the basic meaning.

For example, these would mean roughly the same thing:

• Nobis expedit veritatem statim dicere.
• Nobis expedit statim veritatem dicere.
• Veritatem nobis expedit statim dicere.

The choice of position may slightly affect emphasis or flow, but not the core meaning.

In your sentence, statim sits right next to the infinitive phrase and naturally goes with dicere.

Historically, it is related to the same root as English expedite, but in Latin expedit often means:

• it is useful
• it is advantageous
• it is profitable
• it is expedient
• it is best

So in this sentence, you should not translate it as it speeds up for us. The idiomatic sense is more like:

• It is best for us to tell the truth at once
• It is in our interest to tell the truth immediately

Sometimes in context, yes, but only as a natural English rendering, not as a word-for-word translation.

Literally, nobis expedit means something like:

• it is advantageous for us
• it is in our interest
• it is best for us

Depending on context, English may prefer:

• we should tell the truth immediately

That captures the practical force of the sentence, but it is less literal than the Latin.

So:

• literal sense: it is advantageous for us
• natural sense in context: we should

Because Latin often does not need an expressed dummy subject like English it.

In English, we say:

• It is good to rest.
• It is necessary to leave.
• It is best to tell the truth.

That it does not refer to a real thing; it just fills the subject position.

Latin usually does not need such a filler. It can simply say:

• expedit dicere

So Nobis expedit veritatem statim dicere is perfectly complete without a separate word meaning it.

Yes. Dicere has a broad range of meaning, including to say, to speak, and to tell.

With veritatem, English normally prefers tell the truth rather than say the truth.

So although dicere itself can often be glossed as to say, the best translation here is usually:

• to tell the truth

That is simply the idiomatic English choice.

A helpful breakdown is:

• Nobis = for us
• expedit = is advantageous / is best
• veritatem = the truth
• statim = immediately / at once
• dicere = to tell

Putting that into more natural English gives:

• It is best for us to tell the truth at once.
• It is in our interest to tell the truth immediately.

Those are smoother than a rigidly literal version.