Nisi imber nocte cadat, patruus dicit se cras cum amita et socero et socru ad flumen ambulaturum esse.

Nisi means unless. A very literal way to think of it is if not.

So Nisi imber nocte cadat means Unless rain falls during the night, which in natural English is simply Unless it rains during the night / tonight.

Cadat is the present subjunctive of cadere.

A learner often expects an indicative here, but there are two helpful points:

• the nisi-clause is part of what the uncle is saying, so it is inside reported speech;
• in Latin, subordinate clauses inside indirect speech are often put in the subjunctive.

It also fits the sense of a future, open condition: unless it should rain during the night.

So the subjunctive here does not mean anything wildly different in English; it is mainly a normal Latin way to handle this kind of clause in reported speech.

Latin does not need a dummy subject like English it.

English says it rains, but Latin often uses a real noun as the subject:

• imber cadit = rain falls

So imber is the actual subject of cadat. Literally, the Latin says unless rain falls during the night.

Because Latin often uses the ablative by itself for time expressions.

Here nocte means:

• at night
• during the night

So nocte is an ablative of time. Latin very often does this without in:

• nocte = at night
• tertia hora = at the third hour
• eo die = on that day

They are more specific than English uncle and aunt.

• patruus = father’s brother
• amita = father’s sister

Latin family vocabulary is often more precise than English. English says uncle for several different relationships, but Latin may distinguish them.

Se is the reflexive accusative pronoun, and here it refers back to patruus.

So:

• patruus dicit = the uncle says
• se ... ambulaturum esse = that he will walk

The he is the same person as patruus.

If the sentence meant the uncle says that another man will walk, Latin would normally use eum, not se.

Because after dicit Latin normally uses an indirect statement construction, often called accusative + infinitive.

Instead of saying something like he says that he will walk with a finite verb after that, Latin says:

• dicit
• se ambulaturum esse

In this construction:

• the subject of the reported statement goes into the accusative (se),
• and the verb goes into the infinitive (ambulaturum esse).

Because after verbs of saying, thinking, knowing, hearing, and so on, classical Latin usually prefers indirect statement.

So instead of:

• he says that he will walk

Latin typically says:

• dicit se ambulaturum esse

A useful direct-speech comparison is:

• direct: Cras ... ambulabo = Tomorrow I will walk
• indirect: dicit se cras ... ambulaturum esse = he says that he will walk tomorrow

Ambulaturum esse is the future active infinitive of ambulare.

It is made from:

• the future participle ambulaturus = about to walk / going to walk
• plus esse

Together, they mean:

• to be going to walk
• more naturally in English here, to walk in the future / will walk

So:

• se ambulaturum esse = that he will walk

Because ambulaturum agrees with se, and se is accusative.

The future participle must match the subject of the infinitive in:

• gender
• number
• case

Here se refers to patruus, who is:

• masculine
• singular
• accusative in the indirect statement

So the participle is ambulaturum:

• masculine
• singular
• accusative

If it referred to a woman, it would be ambulaturam.

Because one preposition can govern several nouns.

Here cum takes the ablative, and all three nouns after it are ablative:

• amita
• socero
• socru

So cum amita et socero et socru means with his aunt and father-in-law and mother-in-law. Latin does not need to repeat cum before each noun.

Because it is the ablative singular of socrus.

That form can look strange at first. The important point is:

• cum takes the ablative
• so socrus must appear in the ablative singular: socru

Compare:

• socer → socero in the ablative
• socrus → socru in the ablative

So cum socero et socru = with the father-in-law and mother-in-law.

Latin does not explicitly say his here, but the natural understanding is that they are connected with the person being talked about, namely patruus.

So the most natural reading is:

• the uncle says that he will walk with his aunt, his father-in-law, and his mother-in-law

Latin often leaves possessive words unstated when the relationship is clear enough from context.

Because ad with the accusative usually shows motion toward a place.

So:

• ad flumen = to the river / toward the river

This fits ambulaturum esse, since the idea is movement.

Also, flumen is accusative singular here, because ad takes the accusative.