La inspektoro rigardas la skizon.

The -n is the accusative ending. In Esperanto, this marks the direct object of the verb — the thing being looked at.

• La inspektoro = the inspector
• rigardas = looks / is looking
• la skizon = the sketch

So skizon gets -n because it is the thing the inspector is looking at.

The basic noun is skizo. When it becomes a direct object, it becomes skizon.

Because la inspektoro is the subject, not the direct object.

In Esperanto:

• the subject usually has no special ending
• the direct object takes -n

So in this sentence:

• La inspektoro = the one doing the action
• la skizon = the thing receiving the action

That is why only skizon has -n.

The ending -as marks the present tense in Esperanto.

So rigardas means:

• looks
• is looking
• sometimes simply does look, depending on context

Esperanto uses the same present-tense ending for all persons:

• mi rigardas = I look
• vi rigardas = you look
• li/ŝi rigardas = he/she looks
• ili rigardas = they look

Unlike English, the verb does not change depending on the subject.

La is the Esperanto word for the.

It is used before both nouns here because both are definite:

• la inspektoro = the inspector
• la skizon = the sketch

Unlike English, Esperanto has only one definite article: la. It does not change for gender, number, or case. Even though skizon has -n, the article stays la, not anything else.

In Esperanto, nouns normally end in -o.

So:

• inspektoro = inspector
• skizo = sketch

This is one of the most regular features of Esperanto. If you see a word ending in -o, it is very likely a noun.

If the noun is plural, it becomes -oj:

• inspektoroj = inspectors
• skizoj = sketches

If it is both plural and accusative, it becomes -ojn:

• skizojn = sketches (as direct object)

Yes, Esperanto word order is fairly flexible because the -n ending helps show what the direct object is.

So these all mean essentially the same thing:

• La inspektoro rigardas la skizon.
• La skizon rigardas la inspektoro.
• Rigardas la inspektoro la skizon.

However, the most neutral and common order is subject–verb–object, which is the version you have here.

Even though word order can change, beginners should usually start with the normal order unless there is a special reason to emphasize something.

Yes. In Esperanto, rigardi normally takes a direct object, so it works like look at in English.

• rigardi la skizon = to look at the sketch

English needs the preposition at, but Esperanto does not here. The object is marked directly with -n.

So you should not normally say something equivalent to look at to the sketch. Just use rigardi + direct object.

It can be either, depending on context.

La inspektoro rigardas la skizon can mean:

• The inspector looks at the sketch
• The inspector is looking at the sketch

Esperanto -as does not force the same distinction that English makes between looks and is looking. Context tells you which one is meant.

A careful pronunciation would be approximately:

SKI-zon

More specifically:

• sk as in स्क-like cluster / English sk
• i like ee in see
• z like z in zoo
• o like o in a pure vowel, not a diphthong
• n as usual

The stress in Esperanto is always on the second-to-last syllable, so:

• ski-ZO
• with the accusative ending: ski-ZON

So the stressed syllable is zo.

It is pronounced approximately:

in-spek-TO-ro

The stress is on the second-to-last syllable, so TO is stressed.

A rough English-friendly guide:

• in = like in
• spek = like spek
• to = a clear to
• ro = rolled or tapped r if possible, though beginners are usually understood without a perfect Esperanto r

So the rhythm is:

in-spek-TO-ro

Yes. If the sentence meant the sketches instead of the sketch, you would use the plural ending -j as well as the accusative -n.

• singular: la skizon = the sketch
• plural: la skizojn = the sketches

So:

• La inspektoro rigardas la skizon. = The inspector looks at the sketch.
• La inspektoro rigardas la skizojn. = The inspector looks at the sketches.

Their dictionary forms are:

• rigardi = to look at
• skizo = sketch

In Esperanto, dictionary forms are usually:

• verbs in -i
• nouns in -o

So when you see an inflected form like rigardas, you can recognize the root and know the base form is rigardi. Likewise, skizon goes back to skizo.

It can be, but that changes the meaning slightly.

• La inspektoro rigardas la skizon. = The inspector is looking at the sketch.
• Inspektoro rigardas skizon. = An inspector is looking at a sketch / Inspector looks at sketch, depending on context.

Esperanto has la for definite nouns, but it has no separate word for a/an. If you leave out la, the noun is often understood as indefinite or more general.

So in your sentence, la is there because both nouns are specific.