Etsi dos parva est, pactum familiae placet.

Etsi introduces a concessive idea: although, even though, or sometimes even if.

In this sentence, it is best understood as although/even though:
Etsi dos parva est = Although the dowry is small.

Latin etsi can sometimes shade toward even if, but here the verb est presents the situation as a straightforward fact.

Because etsi often takes the indicative when the speaker presents the clause as real or factual.

So:

• dos parva est = the dowry is small
• this is treated as an actual statement, not a hypothetical one

Latin can use other constructions for more hypothetical or more strongly concessive ideas, but etsi + indicative is very normal.

Dos is singular, not plural.

It is a feminine noun meaning dowry, and here it is the nominative singular, the subject of est.

A useful thing to remember: in Latin, a word ending in -s is not automatically plural.
In fact, dōs, dōtis is a third-declension noun.

So in this sentence:

• dos = subject
• est = singular verb
• therefore dos must be singular here

Because parva is agreeing with dos.

Latin adjectives must agree with the noun they describe in:

• gender
• number
• case

Since dos is:

• feminine
• singular
• nominative

the adjective must also be:

• feminine
• singular
• nominative

So:

• dos parva = a small dowry

Here pactum is a neuter nominative singular noun meaning agreement, compact, or arrangement.

It is the subject of placet.

So the core of the main clause is:

• pactum placet = the agreement pleases / the agreement is pleasing

You may also notice that pactum looks like a participial form. Historically it is related to the verb paciscor (to make an agreement), but in this sentence it is functioning simply as a noun.

Because placet normally takes the person who is pleased in the dative case.

So:

• pactum familiae placet
• literally: the agreement is pleasing to the family

That means familiae is best understood here as dative singular: to the family.

This is a very common Latin pattern:

• mihi placet = it pleases me = I like it
• tibi placet = it pleases you = you like it

So familiae is not the subject. Pactum is the subject.

Formally, yes: familiae can be:

• genitive singular = of the family
• dative singular = to/for the family
• nominative plural = families

But syntax tells us what it is here.

Because the verb is placet, Latin strongly expects:

• the thing liked in the nominative
• the person who likes it in the dative

So in this sentence:

• pactum = nominative subject
• familiae = dative, to the family

That is the natural reading.

Because placet works differently from English likes.

Latin says:

• X alicui placet
• literally: X is pleasing to someone

So the grammar is:

• pactum = the thing that pleases
• familiae = the person/group to whom it is pleasing

In smoother English, that often becomes:

• the family likes the agreement

But the Latin structure is really:

• the agreement pleases the family

This is an important pattern to learn, because verbs like placet do not map exactly onto English wording.

There are two finite verbs here, so it helps to separate the clauses:

1. Etsi dos parva est

   • subject: dos
   • verb: est

2. pactum familiae placet

   • subject: pactum
   • verb: placet
   • dative: familiae

So each clause has its own subject:

• dos for est
• pactum for placet

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

This sentence puts the concessive clause first:

• Etsi dos parva est, ...
• Although the dowry is small, ...

Then it gives the main point:

• pactum familiae placet
• the agreement pleases the family

That order is very natural, because it sets up the contrast first and then gives the result or main statement.

Other word orders are possible, but this one is clear and idiomatic.

Because Latin has no articles.

So Latin nouns by themselves can mean:

• a dowry
• the dowry

or

• an agreement
• the agreement

depending on context.

That means:

• dos could be a dowry or the dowry
• pactum could be an agreement or the agreement

English has to choose, but Latin does not mark that distinction with separate words.