La lando havas novan reĝimon.

Because novan reĝimon is the direct object of the verb havas.

In Esperanto, the direct object usually takes -n. Adjectives must match the noun they describe, so if the noun has -n, the adjective gets -n too.

• reĝimo = regime
• reĝimon = regime, as a direct object
• nova = new
• novan = new, matching a direct object noun

So:

• La lando havas novan reĝimon.
• literally: The country has a new regime.

Havas is the present-tense form of havi, meaning to have.

Esperanto verbs are very regular:

• -as = present tense
• -is = past tense
• -os = future tense
• -us = conditional
• -u = command/wish form

So:

• havas = has / have
• havis = had
• havos = will have

Also, Esperanto verbs do not change for person or number. So:

• mi havas = I have
• vi havas = you have
• la lando havas = the country has
• ili havas = they have

Esperanto has:

• la = the
• no separate word for a/an

So:

• la lando = the country
• nova reĝimo = a new regime or just new regime, depending on context

In this sentence, la lando is definite: it means the country.
But novan reĝimon is indefinite, so Esperanto simply uses the noun phrase without an article.

Because adjectives in Esperanto agree with the nouns they describe.

That means they match in:

• number: singular or plural
• case: especially whether something has the accusative -n

Here, reĝimon is singular and accusative, so the adjective must match:

• nova reĝimo = a new regime
• novan reĝimon = a new regime, as the direct object

If it were plural, you would get:

• novaj reĝimoj = new regimes
• novajn reĝimojn = new regimes, as direct objects

The base form is reĝimo.

Breaking it down:

• reĝimo = regime
• reĝimon = regime + direct object ending -n

So the dictionary form is reĝimo.

This is similar to how English learners might think of dogs under the base form dog. In Esperanto, you remove grammatical endings to find the base form:

• reĝimon → reĝimo
• novan → nova
• lando is already in its base form here

The letter ĝ is pronounced like the j in judge.

So reĝimo is approximately:

• reh-JEE-mo

And the whole sentence is roughly:

• la LAN-do HA-vas no-VAN reh-JEE-mon

A few pronunciation notes:

• Esperanto stress is usually on the second-to-last syllable
• each vowel is pronounced clearly
• ĝ is not like English g in go; it is like English j

Yes, Esperanto word order is fairly flexible, because endings show the grammatical role of words.

The normal, neutral order is:

• La lando havas novan reĝimon.

But you could also say:

• Novan reĝimon havas la lando.

That still means the same thing, because -n on novan reĝimon shows it is the object.

Even so, subject–verb–object is the most common and natural order in ordinary statements, so the original sentence is the best basic version for learners.

Because the sentence is talking about one country, not several.

In Esperanto:

• lando = country
• landoj = countries

So:

• La lando havas novan reĝimon. = The country has a new regime.
• La landoj havas novajn reĝimojn. = The countries have new regimes.

Yes. Reĝimo is a close cognate of English regime.

That can be helpful for English speakers, but it is still good to notice the Esperanto spelling and pronunciation:

• English: regime
• Esperanto: reĝimo

The -o ending shows it is a noun, which is a very common Esperanto pattern:

• nouns end in -o
• adjectives end in -a
• adverbs end in -e

So from the sentence you can immediately see:

• lando = noun
• reĝimo = noun
• nova = adjective
• havas = verb

The subject is la lando.

You can tell because:

• it has no -n
• it is the thing doing the action
• the verb havas describes what the country has

The direct object is novan reĝimon, marked by -n.

So the structure is:

• La lando = subject
• havas = verb
• novan reĝimon = direct object

This is one of the most useful patterns in Esperanto.