Li kontrolas la fulmilon kaj la obturatoron.

In Esperanto, all present-tense verbs end in -as. So kontrolas means checks / is checking.

The verb is built like this:

• kontrol- = the root
• -as = present tense

A useful thing for English speakers: the verb does not change depending on the subject. So:

• mi kontrolas = I check
• li kontrolas = he checks
• ili kontrolas = they check

It is always kontrolas in the present tense.

The -n marks the direct object in Esperanto.

In this sentence, the person is checking two things:

• la fulmilon
• la obturatoron

Those are the things being checked, so both take the accusative ending -n.

Without the -n, they would just be the basic noun forms:

• fulmilo
• obturatoro

With the object marking:

• fulmilon
• obturatoron

In Esperanto, nouns normally end in -o.

So:

• fulmilo is a noun
• obturatoro is a noun

If a noun is a direct object, you add -n, giving -on:

• fulmilo → fulmilon
• obturatoro → obturatoron

So -o tells you this is a noun, and -n adds the idea this noun is the direct object.

Because there are two separate nouns, and each one is definite:

• the flash
• the shutter

So Esperanto naturally uses la before each one:

• la fulmilon
• la obturatoron

Repeating la is clear and normal. English often does the same: the flash and the shutter.

Also, la never changes form in Esperanto. It stays la no matter the gender, number, or case.

Kaj means and.

It joins the two objects together:

• la fulmilon
• la obturatoron

So the full object phrase is the flash and the shutter.

Because both nouns are objects of the same verb, both still take -n.

Li means he.

It is the third-person singular masculine pronoun. It tells us who is doing the action.

So the basic structure is:

• Li = subject
• kontrolas = verb
• la fulmilon kaj la obturatoron = object

A helpful point: even though li means he, the verb does not change. Esperanto does not have a special he checks form different from I check or they check.

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

The most neutral order is:

• Li kontrolas la fulmilon kaj la obturatoron.

But for emphasis, you could also say something like:

• La fulmilon kaj la obturatoron li kontrolas.

That still works because fulmilon and obturatoron are clearly marked as objects by -n.

Even so, the original sentence uses the most ordinary and easiest word order for learners: subject + verb + object.

Yes. Esperanto often builds words from smaller meaningful parts.

Fulmilo can be understood as:

• fulm- = flash / lightning-related root
• -il- = tool or instrument
• -o = noun

So fulmilo is literally something like a flashing device or flash instrument, which fits the idea of a camera flash.

This kind of word-building is very common in Esperanto and is one of the language’s most useful features.

A few useful pronunciation points:

• li sounds like lee
• kaj sounds roughly like kye
• j by itself sounds like English y
• Esperanto stress is usually on the second-to-last syllable

So you get:

• kon-TRO-las
• ful-MI-lon
• ob-tu-ra-TO-ron

That regular stress pattern makes Esperanto pronunciation much more predictable than English.