La paciento havas ne nur dentodoloron, sed ankaŭ ŝvelaĵon.

Because they are the direct objects of havas (has).

In Esperanto, the direct object usually takes the accusative ending -n. So:

• La paciento havas dentodoloron. = The patient has toothache.
• La paciento havas ŝvelaĵon. = The patient has a swelling / swelling.

Without -n, those words would just be their basic dictionary forms:

• dentodoloro
• ŝvelaĵo

In this sentence, both are things that the patient has, so both take -n.

Yes, this is a very common pattern meaning not only ... but also ...

So:

• ne nur dentodoloron = not only toothache
• sed ankaŭ ŝvelaĵon = but also swelling

Together:

• La paciento havas ne nur dentodoloron, sed ankaŭ ŝvelaĵon.

This construction is basically the Esperanto equivalent of English not only ... but also ...

You should learn it as a set phrase:

• ne nur X, sed ankaŭ Y

Sed means but, while ankaŭ means also / too.

In the pattern ne nur ... sed ankaŭ ..., ankaŭ helps complete the idea of not only X, but also Y.

If you said only sed, the sentence would feel incomplete or less balanced:

• ne nur X, sed ankaŭ Y = the standard, natural form

So ankaŭ is there because the second part is an addition, not just a contrast.

It is a compound noun, which is very common in Esperanto.

It breaks down like this:

• dent- = tooth
• dolor- = pain
• -o = noun ending
• -n = accusative ending

So:

• dentodoloro = tooth-pain = toothache
• dentodoloron = toothache (as a direct object)

Esperanto often combines roots into one word where English might use either one word or a phrase.

Compare:

• dentodoloro = toothache
• kapdoloro = headache
• ventrodoloro = stomachache / abdominal pain

Both can make sense, but they are slightly different in feel.

• dentodoloro = toothache, the established idea of pain in a tooth / teeth
• denta doloro = dental pain or tooth-related pain

The compound dentodoloro is more compact and feels like a standard noun. Esperanto often prefers compounds for common concepts.

So in a medical sentence like this, dentodoloro is very natural.

Ŝvelaĵon comes from:

• ŝvela = swollen
• -aĵ- = a concrete thing or manifestation
• -o = noun
• -n = accusative

So:

• ŝvelaĵo = a swelling, a swollen area, something swollen

The suffix -aĵ- often turns a quality or adjective into a concrete thing or result.

For example:

• bela = beautiful
• belaĵo = a beautiful thing

So here:

• ŝvela = swollen
• ŝvelaĵo = a swelling

Usually a swelling is the most precise translation here, because ŝvelaĵo often refers to a specific swollen lump, area, or physical swelling.

So in medical English:

• La paciento havas ŝvelaĵon.
  = The patient has a swelling.

But depending on context, a translator might also say swelling more generally.

La is the Esperanto definite article, meaning the.

So:

• la paciento = the patient

It is used here because the sentence is talking about a specific patient, not just any patient in general.

Esperanto has only one article, la. It does not have separate words for a or an.

Grammatically, you could sometimes omit la, but the meaning would change.

• La paciento = the patient, a specific patient
• paciento = patient, or a patient in a more general/indefinite sense

In a sentence like this, especially in a medical context, la paciento sounds more natural if you mean a particular person being examined or discussed.

Yes, Esperanto word order is fairly flexible, but this order is the most natural here.

The sentence is structured like this:

• La paciento = subject
• havas = verb
• ne nur dentodoloron, sed ankaŭ ŝvelaĵon = the paired object phrase

This is straightforward and easy to understand.

You may see related variations in other sentences, but for learners, the safest model is:

• Subject + verb + ne nur X, sed ankaŭ Y

Ŝ is pronounced like English sh in shoe.

So ŝvelaĵon begins roughly like:

• shve-

A rough pronunciation guide for the whole word is:

• shveh-LAH-jon

And for the full sentence:

• La pa-tsi-EN-to HA-vas ne nur den-to-do-LOR-on, sed an-KOW shveh-LAH-jon

That is only an approximation, but the main thing is:

• ŝ = sh

Yes, paciento is very close to English patient in the medical sense.

It means a person receiving medical care or treatment.

Because Esperanto vocabulary often resembles international words, this one is easy for English speakers to recognize.

• paciento = patient

It usually refers to toothache as a condition, not necessarily pain in exactly one tooth.

Just like English toothache, it can mean pain involving a tooth or teeth in general.

If you needed to be more specific, context would help, but dentodoloro is the normal general word for toothache.

Because Esperanto very often builds words transparently from roots and affixes.

That is one of its main features. Instead of memorizing many unrelated words, you can often understand a word by its parts.

Here:

• dent- = tooth
• dolor- = pain

So dentodoloro is immediately understandable as tooth-pain.

This is very typical Esperanto word formation.