Si culcita satis mollis non est, quid faciamus?

Si means if and introduces a condition.

So the sentence is built like this:

• Si culcita satis mollis non est = If the cushion/mattress is not soft enough
• quid faciamus? = what should we do?

This is a very common Latin pattern:

• si
  • a clause stating the condition
• then the main clause giving the result, question, or response

Culcita is nominative singular.

You can tell because it is the subject of est:

• culcita ... est = the cushion/mattress is ...

So culcita is the thing being described as not soft enough.

It is a first-declension noun, so the nominative singular form ends in -a.

Because mollis belongs to a different adjective pattern.

Mollis, molle is a third-declension adjective, not a first/second-declension one. Its feminine nominative singular is mollis, which matches culcita in:

• gender: feminine
• number: singular
• case: nominative

So even though culcita ends in -a, the adjective does not have to end in -a. It only has to agree grammatically.

That is why:

• culcita mollis = a soft cushion/mattress

Satis means enough, sufficiently, or quite enough.

Here it modifies the adjective mollis:

• mollis = soft
• satis mollis = soft enough / sufficiently soft

So Latin expresses soft enough as literally something like sufficiently soft.

Because non negates the clause, and in Latin it is very commonly placed right before the verb:

• non est = is not

So:

• culcita satis mollis non est = the cushion/mattress is not soft enough

Latin word order is fairly flexible, but non est is a very normal and natural placement.

This is one of the most important grammar points in the sentence.

Faciamus is present subjunctive, first person plural, from facere.

Here it is used as a deliberative subjunctive, which means it asks something like:

• What should we do?
• What are we to do?
• What are we supposed to do?

If Latin used quid facimus?, that would be more like:

• What are we doing?
• or sometimes What do we do?

But quid faciamus? has the sense of asking for a course of action, not just asking what action is happening.

Faciamus is:

• from the verb facio, facere = to do / make
• first person plural = we
• present subjunctive active

So the ending -amus here does not mean ordinary present indicative. In this verb, the subjunctive stem is visible:

• indicative: facimus = we do
• subjunctive: faciamus = may we do / should we do

In this sentence, the natural English translation is what should we do?

Quid means what?

It is the neuter singular form of the interrogative pronoun quis/quid.

Here it is the object of faciamus:

• quid faciamus? = what should we do?

Literally, it is what as the thing to be done.

Because the two clauses are doing different jobs.

In the if-clause, Latin simply states the condition as a real possibility:

• si ... non est = if ... is not

That is why est is indicative.

In the main clause, the speaker is not just stating a fact. They are asking a deliberative question:

• quid faciamus? = what should we do?

That is why Latin uses the subjunctive there.

So the sentence mixes:

• indicative for the condition
• subjunctive for the question about what action to take

Yes, it is a conditional sentence, but not the classic if X happens, Y will happen type.

It has:

• a condition: Si culcita satis mollis non est
• a deliberative question in response: quid faciamus?

So it means something like:

• If the cushion/mattress is not soft enough, what should we do?

The if-clause is a fairly straightforward open condition with present indicative. The second half is not a normal result statement; it is a question using the subjunctive.

Yes, this word order is normal.

Latin often places the if-clause first, then the main clause:

• Si ... , quid ... ?

Within the first clause:

• culcita satis mollis non est

is also natural. Latin often puts descriptive words near the noun, but it does not have to be as rigid as English.

You could find other arrangements in Latin, such as moving non or satis for emphasis, but the version here is perfectly standard and easy to read.

It can refer to a cushion, mattress, or padded seat/bed covering, depending on context.

Latin words for household objects often cover a somewhat wider range than a single exact English word. So the best translation depends on the situation.

For grammar purposes in this sentence, the key thing is that culcita is the subject and is being described as not soft enough.

Yes. Quid facere debemus? would mean something like What ought we to do? or What must we do?

But that is a different construction.

• quid faciamus? uses the subjunctive
• quid facere debemus? uses debeo
  • infinitive

Both can express obligation or practical choice, but quid faciamus? is a very idiomatic Latin way to ask a deliberative question: What should we do?