Asinus plaustrum trahit, sed una rota male vertitur.

Asinus is nominative singular, the case used for the subject of the sentence.

In Asinus plaustrum trahit, the donkey is the one doing the action of pulling, so Latin puts asinus in the nominative.

A learner might compare:

• asinus = the donkey / a donkey as subject
• asinum = the donkey as direct object

So asinus trahit means the donkey pulls, not someone pulls the donkey.

Plaustrum is the direct object of trahit, so it is in the accusative singular.

The thing being pulled is the cart, so Latin uses the object case:

• asinus = subject
• plaustrum = object

A useful detail: plaustrum is a neuter noun of the second declension, and neuter nouns often have the same form in nominative and accusative singular. So even though plaustrum looks like it could be either subject or object, its role here is clear from the sentence structure and the verb.

Trahit is:

• 3rd person singular
• present tense
• active voice
• from trahere = to pull, drag

So trahit means he/she/it pulls.

Because the subject is asinus, we understand it as the donkey pulls.

The ending -t is very important: it tells you the verb has a singular third-person subject.

Because rota is a feminine noun, and the adjective/numeral meaning one must agree with it.

So:

• unus = masculine
• una = feminine
• unum = neuter

Since rota is feminine, Latin says una rota.

This is a very common pattern in Latin: adjectives agree with the nouns they describe in gender, number, and case.

Una rota is nominative singular.

It is the subject of the second clause:

sed una rota male vertitur

That means one wheel is the thing associated with the action of vertitur.

So the sentence has two separate clauses:

• Asinus plaustrum trahit
• sed una rota male vertitur

Each clause has its own subject:

• asinus
• una rota

Vertitur is the 3rd person singular present passive form of vertere.

So literally it means something like:

• is turned
• turns in a passive-like or middle sense

In smoother English, this is often translated simply as turns or rotates.

This is one of those places where Latin and English do not line up perfectly. Latin may use a passive form where English prefers a more natural active-style verb:

• rota vertitur = the wheel turns / the wheel is turning

By contrast:

• vertit would mean he/she/it turns something

So:

• rota vertitur = the wheel turns
• aliquis rotam vertit = someone turns the wheel

Because male is an adverb, and it modifies the verb vertitur.

It tells us how the wheel turns:

• male = badly, poorly

If you used mala, that would be an adjective form, not an adverb. An adjective would have to describe a noun, not a verb.

So:

• mala rota = a bad wheel
• rota male vertitur = the wheel turns badly

That distinction is very important in Latin:

• adjective modifies a noun
• adverb modifies a verb, adjective, or another adverb

Sed means but.

It joins the two clauses and shows a contrast:

• the donkey is pulling the cart,
• but one wheel is turning badly.

It is a very common coordinating conjunction in Latin.

Latin usually has no articles.

So asinus can mean:

• a donkey
• the donkey

and plaustrum can mean:

• a cart
• the cart

The exact choice in English depends on context.

That is normal in Latin. Learners often want to know where the is, but usually there simply is no separate word for it.

Latin word order is more flexible than English word order because the endings show the grammatical roles.

So this sentence could be rearranged in several ways and still mean basically the same thing, because:

• asinus is nominative
• plaustrum is accusative
• rota is nominative
• trahit and vertitur show the actions

That said, word order still affects style, emphasis, and flow.

The given order is very natural:

• Asinus plaustrum trahit
• sed una rota male vertitur

It presents the action clearly and then adds the contrasting problem.

Because this is really two clauses joined by sed:

1. Asinus plaustrum trahit
2. sed una rota male vertitur

Each clause has its own subject and verb:

• asinus ... trahit
• una rota ... vertitur

This is very common in Latin, just as in English:

• The donkey pulls the cart, but one wheel turns badly.

So a learner should not try to make asinus the subject of both verbs. The second clause starts a new statement with a new subject.

Yes: rota is a first-declension feminine noun.

Its basic forms would be something like:

• nominative singular: rota
• genitive singular: rotae

In this sentence, rota is nominative singular because it is the subject of vertitur.

A learner may notice that rota looks very much like the English word rotary or related wheel-words in Romance languages. That can help with memory.

Yes, literally that is possible, but in normal English it often sounds better as turns badly or does not turn properly.

That is a helpful reminder: when reading Latin, it is good to know both:

• the literal grammatical value
• the natural English meaning

So for this phrase:

• literal: one wheel is turned badly
• natural: one wheel turns badly

Both reflect the same Latin form, but the second is usually better English in context.