Sive semis sive uncia legatario datur, coheres testamentum legit.

Sive ... sive is a correlative pair meaning whether ... or or sometimes either ... or.

So Sive semis sive uncia ... means whether a half or an ounce .... It sets up two alternatives without changing the main point of the sentence.

Latin has several ways to say or, and they are not always used in exactly the same way.

• sive ... sive often introduces alternatives in a neutral, explanatory, or legal style.
• aut ... aut can sound more strongly exclusive: either this or that.
• vel ... vel can be looser: this or that, sometimes even.

In a sentence like this, especially in a formal or legal context, sive ... sive is very natural for presenting two possible cases.

Both semis and uncia are nominative singular here, because they are the grammatical subject of the passive verb datur.

In English, the thing given is the subject of a passive verb:

• a half is given
• an ounce is given

That is exactly what happens in Latin here.

A learner may pause over semis, because it is not a very common noun and its forms are a bit irregular. But in this sentence, it is functioning just like uncia: it is one of the possible subjects of datur.

Because the sentence does not mean that both are given together. It means one or the other.

The structure sive ... sive presents alternatives:

• either a half is given
• or an ounce is given

Since each alternative is singular, the verb is singular too: datur = is given.

If the sentence meant that both things were given together, a plural verb would be more likely.

Legatario is dative singular, meaning to the legatee.

With verbs of giving, Latin often uses:

• nominative for the thing given
• dative for the person receiving it

So:

• semis / uncia = the thing given
• legatario = the recipient

Latin does not need a preposition here, because the dative ending itself already shows the meaning to or for.

Datur is:

• 3rd person singular
• present tense
• indicative mood
• passive voice

It comes from do, dare = to give.

So datur means is given.

That passive form is why the thing given becomes the subject of the clause.

Coheres is the subject of legit.

It is nominative singular and means co-heir. In other words, it names the person who performs the action of legit.

So in the second clause:

• coheres = subject
• testamentum = object
• legit = verb

They are two different legal roles.

• legatarius = a legatee, someone who receives a specific gift or bequest
• coheres = a co-heir, someone who shares in the inheritance as an heir

So the sentence contrasts two people involved in inheritance law:

• the legatee receives something
• the co-heir does the action in the main clause

Because it is the direct object of legit.

The verb lego, legere takes a direct object when it means read (or whatever specific meaning the context has already given you). So testamentum is the thing affected by the action.

That is why it appears in the accusative singular:

• coheres = subject
• testamentum = direct object
• legit = verb

Yes. In form alone, legit can be ambiguous.

From lego, legere, legit can be:

• present: he/she reads
• perfect: he/she read or has read

So how do you decide? By context.

Here the sentence has a general, legal-style feel, and the earlier verb datur is present. That makes it most natural to take legit as present too.

So a learner would normally understand it as present unless the wider context clearly pointed to past time.

Because Latin relies much more on case endings than on word order.

In English, word order tells us who is doing what. In Latin, endings often do that job instead. That gives Latin more freedom to arrange words for emphasis or style.

Here the sentence puts the alternatives first:

• Sive semis sive uncia
• then the recipient: legatario
• then the verb: datur

After that comes the main clause:

• coheres testamentum legit

A very literal English order may sound unusual, but the Latin order is perfectly normal.

Because classical Latin has no articles.

So a noun like testamentum can mean:

• a will
• the will

and coheres can mean:

• a co-heir
• the co-heir

Context tells you which is best in translation. English has to choose an article, but Latin usually does not state one.

Yes, that is a good way to understand it.

The sive ... sive clause gives the circumstance or alternative case:

• whether a half or an ounce is given to the legatee

Then the main clause states what happens:

• the co-heir reads the will

So the sentence is built as:

1. alternative condition/case
2. main statement

That kind of structure is especially common in formal and legal language.