La gingivo estas sentema.

La is the definite article, meaning the.

So La gingivo means the gum or the gum tissue. Esperanto has only one definite article: la. It does not change for gender, number, or case.

In Esperanto, nouns end in -o.

So:

• gingiv- = the word root
• -o = noun ending

That tells you gingivo is a noun.

Yes, gingivo is singular.

To make it plural, Esperanto adds -j:

• gingivo = gum
• gingivoj = gums

In a medical or general statement, Esperanto may use the singular to talk about gum tissue as a whole. If you specifically mean multiple gums, you would use gingivoj.

Estas means is / am / are.

It is the present-tense form of esti = to be.

Examples:

• mi estas = I am
• vi estas = you are
• ŝi estas = she is
• la gingivo estas = the gum is

Esperanto uses the same present-tense form estas for all subjects.

Because sentema is an adjective, and adjectives in Esperanto end in -a.

So:

• sentem- = the adjective root/base
• -a = adjective ending

In this sentence, sentema describes gingivo, so it works like sensitive in English.

Sentema means sensitive.

It is built from meaningful parts:

• sent- = feel
• -em- = inclined to, prone to
• -a = adjective

So the idea is something like prone to feeling strongly / easily affected. In normal English, the best translation is simply sensitive.

Because there is no direct object.

In La gingivo estas sentema:

• La gingivo is the subject
• estas links the subject to a description
• sentema is a predicate adjective, not an object

The accusative -n is usually used for direct objects, so it is not needed here.

Yes. In Esperanto, adjectives agree with the nouns they describe in number, and also in case when relevant.

Here the noun is singular:

• La gingivo estas sentema.

If the noun were plural, the adjective would also be plural:

• La gingivoj estas sentemaj. = The gums are sensitive.

So sentema is singular because gingivo is singular.

This is the most basic and neutral word order:

• La gingivo = subject
• estas = verb
• sentema = description

So it follows the common pattern subject + verb + complement.

Esperanto word order is fairly flexible, but this version is the most straightforward and natural for a learner.

A simple guide:

• gingivo: hard g, not English j; stress on the second syllable
  Roughly: gin-GEE-vo
• sentema: stress on TE
  Roughly: sen-TE-ma

Full sentence:

• La gingivo estas sentema
• Roughly: la gin-GEE-vo ES-tas sen-TE-ma

A useful rule: Esperanto stress is normally on the second-to-last syllable.

Esperanto often prefers words built regularly from roots and affixes.

Sentema is a very natural Esperanto-style formation:

• sent- = feel
• -em- = prone to
• -a = adjective

So even if an English speaker expects something closer to sensitive, Esperanto may instead use a word built from its own internal logic. Learning to notice these parts helps a lot.

Yes, it can.

Depending on context, la can point to:

• a specific gum already being discussed, or
• the gum as a known anatomical thing

So the sentence can work either as:

• a statement about a particular person's gum, or
• a general anatomical statement, depending on context

Context usually makes this clear.