Serva pistillo parvo utitur, dum allium et salem in mortario miscet.

Serva is the subject of the sentence, so it appears in the nominative singular.

• serva = the female slave / maidservant
• It is a first-declension noun.
• Its nominative singular ending is -a.

So serva ... utitur ... miscet means that the serva is the one doing the actions.

Because the verb utor, uti, usus sum (to use) takes the ablative case, not the accusative.

So:

• pistillo = ablative singular of pistillum (pestle)
• parvo = ablative singular of parvus (small)

Together, pistillo parvo means with a small pestle or using a small pestle.

This is one of the most important things to notice in the sentence: utor does not work like the English verb use.

It looks passive, but it is actually active in meaning. Utor is a deponent verb.

That means:

• it has passive-looking forms
• but an active meaning

So:

• utitur literally looks like a passive form
• but it means she uses, not she is used

This is very common with deponent verbs in Latin.

Utitur is:

• 3rd person singular
• present tense
• indicative mood
• from the deponent verb utor, uti, usus sum

So it means she uses.

The ending -tur is one of the normal passive/deponent present endings.

Because parvo is an adjective modifying pistillo, and adjectives must agree with the nouns they describe in:

• gender
• number
• case

Here:

• pistillo = masculine/neuter? Actually pistillum is neuter, so pistillo is neuter ablative singular
• parvo = neuter ablative singular

So parvo matches pistillo exactly.

Dum here means while.

It introduces an action happening at the same time as the main action:

• Serva pistillo parvo utitur
• dum allium et salem in mortario miscet

So the servant uses a small pestle while she is mixing the garlic and salt.

Depending on context, dum can have other meanings in Latin, but while is the natural one here.

Because the two actions are happening at the same time:

• she uses the pestle
• while she mixes the garlic and salt

So Latin uses the present tense for both verbs:

• utitur
• miscet

This is a normal way to describe simultaneous action.

They are both in the accusative singular, because they are the direct objects of miscet (mixes). They look different because they belong to different declensions.

• allium is a 2nd-declension neuter noun
  
  • nominative/accusative singular: allium
• sal is a 3rd-declension noun
  
  • accusative singular: salem

So both are objects, but they decline differently.

Because in with the ablative usually means in/on in the sense of location.

Here the meaning is in the mortar, meaning the mixing is taking place there.

So:

• in mortario = in the mortar

If in took the accusative, it would usually suggest motion into something.

Mortario is ablative singular of mortarium (mortar).

It is ablative because it follows in with the meaning of location:

• in mortario = in the mortar

So there are actually two ablatives in the sentence, but for different reasons:

• pistillo parvo after utor
• in mortario after in meaning location

A simple way to divide it is:

• Serva = subject
• pistillo parvo = ablative with utitur
• utitur = main verb
• dum = introduces a subordinate clause
• allium et salem = direct objects of miscet
• in mortario = location
• miscet = verb of the subordinate clause

So the sentence has:

1. a main clause: Serva pistillo parvo utitur
2. a dum-clause: dum allium et salem in mortario miscet

Yes, but it is also very normal Latin.

Latin word order is more flexible than English because endings show the grammatical relationships. In this sentence:

• Serva comes first as the subject
• utitur is placed after its ablative phrase
• the dum clause comes after the main clause
• miscet comes at the end of its clause, which is very common in Latin

A more literal English-like order might be something like:

• Serva utitur pistillo parvo, dum miscet allium et salem in mortario

But the original order sounds natural in Latin.

Yes, and that is often the best way to help yourself understand the grammar.

Because utor takes the ablative, English with can be useful for remembering the construction:

• pistillo parvo utitur = she uses a small pestle
• or more literally, she makes use of a small pestle / she uses with a small pestle

The normal English translation will still usually be uses a small pestle, but the with idea helps explain the Latin case.

Yes. Et means and, and it links the two accusative objects of miscet:

• allium
• salem

So she is mixing garlic and salt.

This is straightforward coordination: both nouns depend on the same verb, miscet.