Nauta in tempestate perit.

Because nauta is a first-declension noun, and many first-declension nouns end in -a in the nominative singular. Although first-declension nouns are often feminine, some are masculine, especially words for traditionally male occupations, such as nauta (sailor) and agricola (farmer).

So -a does not always mean the noun is feminine.

Nauta is nominative singular. The nominative case is normally used for the subject of the sentence.

We know it is the subject because:

• it is in the nominative form
• perit is a third-person singular verb, so it matches a singular subject

So nauta is the sailor as the one doing the action of perit.

Perit is:

• present tense
• indicative mood
• active voice
• third person singular

It comes from pereo, perire, meaning to perish, to die, or to be destroyed.

So perit means he/she/it perishes or dies. Here it refers to nauta, so it means the sailor perishes.

Because tempestate is the ablative singular form of tempestas, tempestatis (storm, tempest).

The preposition in here takes the ablative because it expresses being in something or within a situation, not movement into it.

So:

• tempestas = nominative singular
• tempestate = ablative singular

That is why Latin says in tempestate.

Grammatically, in tempestate is a prepositional phrase:

• in = a preposition
• tempestate = ablative singular object of the preposition

Here in + ablative means something like:

• in the storm
• amid the storm
• sometimes more loosely during the storm

It describes the circumstance or setting in which the sailor perishes.

Latin does not have articles like English the and a/an.

So nauta can mean:

• a sailor
• the sailor

And tempestate can mean:

• in a storm
• in the storm

The exact choice in English depends on the context and on what sounds most natural in translation.

Yes. In can take either the ablative or the accusative, depending on the meaning.

• in + ablative = in / on with no motion, or within a situation
  
  • as in in tempestate
• in + accusative = into / onto, showing motion toward something

So this sentence uses in + ablative because it is not about moving into the storm, but about being or happening within the storm.

Not as much as in English. Latin word order is more flexible because the endings show how words function in the sentence.

So the basic meaning would stay the same even if the words were rearranged, for example:

• In tempestate nauta perit
• Perit nauta in tempestate

Still, Nauta in tempestate perit is a perfectly normal order. It presents:

• the subject first
• then the prepositional phrase
• then the verb at the end, which is very common in Latin

Because both the noun and the verb are singular.

• nauta = nominative singular
• perit = third-person singular

If the sentence meant sailors perish in the storm, Latin would use plural forms, such as:

• nautae for sailors
• pereunt for they perish

So the forms clearly show that the subject is singular.

Tempestas, tempestatis is a third-declension noun.

That is why its ablative singular is tempestate, not something like tempestā. Third-declension nouns often have different stem changes and endings from first- and second-declension nouns.

So in this sentence you are seeing:

• nauta = first declension
• tempestas = third declension
• perit = a verb form

This is a good example of how Latin combines different declensions in one short sentence.