La kartono estas en la malnova skatolo.

In Esperanto, word endings tell you what kind of word something is.

• kartono: the -o shows it is a noun
• skatolo: also a noun
• malnova: the -a shows it is an adjective

So in this sentence:

• kartono = a noun
• skatolo = a noun
• malnova = an adjective describing skatolo

This is one of the most regular parts of Esperanto grammar.

Because malnova is an adjective describing skatolo, and adjectives in Esperanto normally end in -a.

• nova = new
• malnova = old

The prefix mal- makes the opposite of a word. So:

• nova = new
• mal-nova = not new, old

This is a very common pattern in Esperanto.

In Esperanto, adjectives usually come before the noun, just as they often do in English:

• la malnova skatolo = the old box

But Esperanto is more flexible than English. You can also say:

• la skatolo malnova

That is grammatical, though less common in ordinary neutral usage. Learners will most often see and use the adjective before the noun.

Because this sentence shows location, not movement.

• en la malnova skatolo = in the old box

Here, the cardboard is already inside the box, so no accusative -n is needed.

Esperanto often uses -n after a preposition when there is movement toward a place. For example:

• La kartono iras en la malnovan skatolon. = The cardboard goes into the old box.

So the difference is:

• en la malnova skatolo = in the old box, located there
• en la malnovan skatolon = into the old box, motion toward it

Estas is the present-tense form of esti, which means to be.

So:

• mi estas = I am
• vi estas = you are
• ĝi estas = it is

In this sentence, estas links the subject with its location:

• La kartono estas en la malnova skatolo.
• The cardboard is in the old box.

Esperanto uses the same present-tense form estas with all persons and numbers, which makes it much simpler than English.

Because both noun phrases are definite.

• La kartono = the cardboard
• la malnova skatolo = the old box

Esperanto has only one definite article: la. It does not change for gender, number, or case.

Also, Esperanto normally has no indefinite article. So:

• kartono can mean a cardboard piece / cardboard / a carton, depending on context
• la kartono means the cardboard

Using la twice is normal here because both things are being treated as specific.

Not always exactly. Esperanto words do not always match one English word perfectly in every context.

Kartono often refers to:

• cardboard
• stiff paperboard
• sometimes a carton-like object, depending on context

So the exact English translation can vary. That is normal in language learning. Even if the meaning has already been given to you, it is good to remember that Esperanto words often cover a range that does not line up perfectly with just one English word.

Yes. Esperanto word order is fairly flexible because the grammar is shown clearly by endings and function words.

The most neutral order here is:

• La kartono estas en la malnova skatolo.

But other orders are possible, for example:

• En la malnova skatolo estas la kartono.

That version puts more focus on the location. It is still grammatical.

Even so, beginners should usually start with the most straightforward order: subject + verb + other information.

A simple pronunciation guide for an English speaker is:

• La = lah
• kartono = kahr-TOH-no
• estas = ES-tahs
• en = en
• la = lah
• malnova = mahl-NOH-vah
• skatolo = skah-TOH-lo

A few useful pronunciation points:

• every vowel is pronounced clearly
• stress is usually on the second-to-last syllable
• o is always like a clear o
• a is like ah

So:

• karTOno
• EStas
• malNOva
• skaTOlo

Yes, but it changes the meaning.

• La kartono estas en la malnova skatolo. = The cardboard is in the old box.
• Kartono estas en malnova skatolo. = Cardboard / a piece of cardboard is in an old box.

Without la, the sentence sounds less definite and less specific.

So whether you use la depends on whether you mean a particular thing or just something non-specific.