Ŝi promenigas la hundon hodiaŭ.

Because promenigi means to make someone or something take a walk or, in natural English, to walk someone/something.

• promeni = to walk, to take a walk, to stroll
• -ig- = a suffix meaning to cause to do something or to make become

So:

• Ŝi promenas = She is walking / taking a walk
• Ŝi promenigas la hundon = literally She is causing the dog to walk, which is how Esperanto expresses She is walking the dog

This is a very common and important Esperanto pattern.

-ig- is the causative suffix. It means to cause, to make, or to render.

In this sentence:

• promeni = to walk
• promenigi = to make walk / to take for a walk

A few similar examples:

• sidi = to sit

• sidigi = to make someone sit, to seat someone

• boli = to boil

• boligi = to make something boil

• ruĝi = to be red
• ruĝigi = to make red

So promenigas is built very regularly: promen- + ig + as

The ending -as marks the present tense.

So promenigas means is walking or walks, depending on context.

Esperanto tense endings are very regular:

• -as = present
• -is = past
• -os = future
• -us = conditional
• -u = command / jussive

Examples:

• Ŝi promenigas la hundon. = She walks / is walking the dog.
• Ŝi promenigis la hundon. = She walked the dog.
• Ŝi promenigos la hundon. = She will walk the dog.

The -n shows that la hundon is the direct object of the sentence.

In other words, the dog is the one receiving the action of promenigas.

• la hundo = the dog
• la hundon = the dog, as a direct object

This is called the accusative ending.

Compare:

• La hundo promenas. = The dog is walking.
  Here la hundo is the subject, so no -n.

• Ŝi promenigas la hundon. = She is walking the dog.
  Here la hundon is the object, so it takes -n.

La is the Esperanto definite article, meaning the.

So:

• hundo = dog / a dog
• la hundo = the dog

Esperanto has only one article, la, and it does not change for gender, number, or case. Even when the noun gets -n, the article stays the same:

• la hundo
• la hundon

Unlike English, Esperanto has no separate word for a/an. So hundo can mean a dog or just dog, depending on context.

Yes. Esperanto word order is fairly flexible because endings show grammatical roles.

The standard order here is:

• Ŝi = subject
• promenigas = verb
• la hundon = object
• hodiaŭ = today

But you could also say:

• Hodiaŭ ŝi promenigas la hundon.
• La hundon ŝi promenigas hodiaŭ.

These all mean basically the same thing, though the emphasis changes.

Because la hundon has -n, you can still tell it is the object even if it moves around.

That said, learners should usually start with the most neutral order: subject + verb + object + time expression

No. Hodiaŭ can appear in different places in the sentence.

All of these are possible:

• Ŝi promenigas la hundon hodiaŭ.
• Hodiaŭ ŝi promenigas la hundon.
• Ŝi hodiaŭ promenigas la hundon.

The version with hodiaŭ at the end is perfectly natural. Moving it changes the emphasis slightly, but not the basic meaning.

Yes, but the meaning is a little different.

• Ŝi promenigas la hundon. = She is walking the dog.
  This focuses on her taking the dog out for a walk.

• Ŝi promenas kun la hundo. = She is walking with the dog.
  This simply says she is walking and the dog is with her.

In many real situations, both could describe the same event, but promenigas la hundon is the more direct equivalent of English walk the dog.

Ŝi means she.

The letter ŝ is pronounced like English sh in shoe.

So Ŝi is pronounced roughly like shee.

A few helpful points:

• ŝ = sh
• i = an ee sound

So the whole word is very straightforward once you know the alphabet.

Hodiaŭ is pronounced roughly hoh-DEE-ow.

Useful details:

• ho = like ho in hope, but shorter
• di = dee
• aŭ = a diphthong somewhat like ow in cow

The stress in Esperanto normally falls on the second-to-last syllable, so in hodiaŭ the stress is on di: ho-DI-aŭ

No. Grammatically, it can be used for any person or thing that is being made to walk or taken for a walk.

Examples:

• Ŝi promenigas la hundon. = She is walking the dog.
• La gepatro promenigas la infanon. = The parent is taking the child for a walk.
• Li promenigis la ĉevalon. = He walked the horse / took the horse out.

So the structure is general, even if walking a dog is one of the most common situations.

Esperanto often builds meanings very economically from smaller parts.

Instead of having a completely separate verb, it uses:

• promeni = to walk
• -ig- = to make/cause

So promenigi neatly gives the idea to make take a walk.

This is one of the strengths of Esperanto: once you know the building blocks, many words become easy to understand and create.