Li redaktas portreton same kiel memfoton.

Because both are functioning as direct objects.

• portreto = portrait
• portreton = portrait as the object of the verb
• memfoto = selfie
• memfoton = selfie as the object of the verb

In Esperanto, the direct object usually takes the -n ending.
Here, Li redaktas portreton means He edits a portrait.

The -n on memfoton is there because it is being compared in the same grammatical role: the sentence is basically saying he edits a portrait in the same way that he edits a selfie.

same kiel means like, just like, or in the same way as.

A helpful breakdown is:

• same = similarly, in the same way
• kiel = as, like

So same kiel memfoton means something like just like a selfie or in the same way as a selfie.

It is a very common Esperanto pattern for making comparisons.

Esperanto does not have an indefinite article.

English has:

• a portrait
• a selfie

Esperanto simply says:

• portreto
• memfoto

Esperanto does have a definite article, la, for the, but there is no separate word for a/an.

So:

• portreton = a portrait or the portrait, depending on context
• memfoton = a selfie or the selfie, depending on context

Yes, it is one word, and it is a compound noun.

It is built from:

• mem = self
• foto = photo

So:

• memfoto = self-photo, meaning selfie
• memfoton = selfie as a direct object

Compounds are very common in Esperanto. Usually, the main idea comes at the end. Here, the main noun is foto, and mem modifies it.

redaktas is the present-tense form of the verb redakti, meaning to edit.

Esperanto verb endings are regular:

• -i = infinitive, to edit → redakti
• -as = present tense, edits / is editing
• -is = past tense
• -os = future tense

So:

• Li redaktas = He edits or He is editing

One nice thing about Esperanto is that verb forms do not change depending on the subject.
So:

• mi redaktas
• li redaktas
• ili redaktas

all use -as for the present tense.

Yes, to some extent.

The most neutral order is:

• Li redaktas portreton same kiel memfoton.

But Esperanto allows some flexibility because the -n ending shows which noun is the direct object.

For example, portreton li redaktas... would still be understandable, though it would sound more marked or emphatic.

So the usual order here is preferred, but the grammar does not depend only on position the way English often does.

Because it matches the grammatical role of portreton.

Even though kiel introduces a comparison, memfoton still represents something being compared as an object. You can think of it as a shortened version of a fuller idea, something like:

• Li redaktas portreton same kiel li redaktas memfoton.

In the shorter version, the second verb is omitted, but memfoton keeps the object ending because it still belongs to that same structure.

This is a point that can feel unusual to English speakers, since English does not mark direct objects with a special ending.

Because it is the first word of the sentence.

In Esperanto, pronouns are normally lowercase:

• li = he

But like in English, the first word of a sentence is capitalized:

• Li redaktas...

So this is just normal capitalization, not a special grammatical form.