Promenigu ĝin nur se ĝi portas kolumon kaj kondukŝnuron.

Promenigu comes from:

• promen- = walk, stroll
• -ig- = make/cause someone or something to do something
• -u = command/request/instruction ending

So promenigi means to make something walk, which in normal English is to take it for a walk or to walk it.

That is why Promenigu ĝin means Walk it / Take it for a walk.

By contrast, promeni means to walk oneself. So Promenu! means Walk! or Take a walk! It does not mean walk it.

The ending -u is the Esperanto form used for:

• commands
• requests
• instructions
• wishes

So Promenigu ĝin is an instruction, like something you might see in a rule or notice.

In English, this often corresponds to the plain imperative:

• Walk it
• Take it for a walk

In Esperanto, commands often leave the subject unstated, just like English does.

English says:

• Close the door.
• Be careful.

Esperanto does the same:

• Fermu la pordon.
• Atentu.

So in Promenigu ĝin, the understood subject is you, but it does not need to be said.

Because the pronoun has a different job in each part of the sentence.

• Promenigu ĝin: here ĝin is the direct object, so it takes -n
• se ĝi portas...: here ĝi is the subject of portas, so there is no -n

So:

• ĝi = it, as subject
• ĝin = it, as direct object

This is a very common Esperanto pattern.

In Esperanto, ĝi is the normal pronoun for an animal when:

• its sex is unknown
• its sex is irrelevant
• the speaker is being neutral

So ĝi here is grammatically normal.

If the animal’s sex were known and relevant, someone could also say:

• li for a male animal
• ŝi for a female animal

People also sometimes use li or ŝi for pets they feel close to, but ĝi is standard and not wrong.

Yes. Porti can mean:

• to carry
• to wear
• to bear

So with things like clothing or attached items, portas can mean wears or has on.

That is why:

• ĝi portas kolumon = it is wearing a collar

This verb is broader than English wear. Esperanto often uses porti in places where English would say wear, carry, or sometimes have on.

Because both are direct objects of portas.

The structure is:

• ĝi portas kolumon kaj kondukŝnuron

The animal is wearing/carrying both things, so both nouns get the accusative ending -n.

Compare:

• Mi portas sakon. = I’m carrying a bag.
• Ĝi portas kolumon. = It is wearing a collar.

When two direct objects are joined by kaj, each one keeps its own -n.

Kondukŝnuron is a compound word.

It can be broken down as:

• konduk- = lead, guide
• ŝnur- = cord, string
• -o = noun ending
• -n = direct object ending

So kondukŝnuro is literally something like guiding-cord or leading-cord, which is why it means leash or lead.

Esperanto forms many words this way. Long-looking words are often just smaller meaningful parts combined together.

Nur se means only if.

So the instruction applies on one condition only:

• Promenigu ĝin nur se... = Walk it only if...

The placement of nur matters. In this sentence, nur limits the condition introduced by se.

If nur were placed elsewhere, the meaning would change. For example:

• Promenigu nur ĝin... = Walk only it...
• ĝi portas nur kolumon... = it is wearing only a collar...

So here nur se clearly means only if.

Yes. Kaj means and, so both items are required:

• kolumon = a collar
• kondukŝnuron = a leash

If the meaning were either one is enough, Esperanto would use aŭ instead of kaj.

So this sentence means the condition is satisfied only when both are present.