Mi subskribas la formularon kaj ricevas bibliotekkarton.

In Esperanto, -as is the present-tense verb ending. It means the action is happening now or is generally true.

So:

• subskribas = sign / am signing
• ricevas = receive / am receiving

Every present-tense verb uses -as, no matter who the subject is. Unlike English, the verb does not change for I, you, he, etc.

• mi subskribas = I sign
• vi subskribas = you sign
• li subskribas = he signs

The -n marks the direct object in Esperanto. The direct object is the thing directly affected by the verb.

Here, the thing being signed is the form, so:

• la formularo = the form
• la formularon = the form (as the direct object)

In the sentence:

• Mi subskribas la formularon = I sign the form

The same idea appears in bibliotekkarton:

• Mi ricevas bibliotekkarton = I receive a library card

Both formularon and bibliotekkarton are objects, so both take -n.

La means the.

So:

• la formularon = the form
• bibliotekkarton = a library card or just library card, depending on context

Esperanto has a definite article (la) but no indefinite article. So Esperanto does not have a separate word for a/an.

That means:

• formularo can mean a form
• la formularo means the form

In this sentence, the speaker is talking about a specific form, so la is used. But bibliotekkarton has no la, so it is understood as a library card.

Because the subject is still understood to be the same: mi.

Esperanto often leaves out a repeated subject when two verbs are joined by kaj (and) and the subject has not changed.

So:

• Mi subskribas la formularon kaj ricevas bibliotekkarton.

means:

• Mi subskribas la formularon kaj mi ricevas bibliotekkarton.

Both are grammatical, but the version without the repeated mi is more natural here.

Kaj means and.

It joins the two actions:

• subskribas la formularon = sign the form
• ricevas bibliotekkarton = receive a library card

So the sentence says that both actions happen:

• I sign the form and receive a library card.

It is a compound word:

• biblioteko = library
• karto = card

Together:

• bibliotekkarto = library card

Then it gets -n because it is the direct object:

• bibliotekkarton

Notice that in compounds, Esperanto commonly joins roots directly. The meaning is usually very transparent.

Esperanto usually prefers compound words when English would also naturally treat something as a single concept.

So library card becomes one word:

• bibliotekkarto

This is very common in Esperanto. The first part modifies the second part.

Other examples:

• vortaro = word-book = dictionary
• manĝotablo = eating-table = dining table

Writing biblioteko karto as two separate nouns would sound unusual.

The sentence follows a very common Esperanto order:

• Mi = subject
• subskribas = verb
• la formularon = object
• kaj ricevas = and receive
• bibliotekkarton = object

So it is basically subject–verb–object, like normal English word order.

Esperanto word order is more flexible than English because the -n ending shows the object, but the standard order is still the most common and easiest to understand.

Yes, historically that is the idea.

• sub = under
• skribi = to write

So subskribi literally suggests write underneath, which developed into the meaning sign.

This kind of word-building is very common in Esperanto and can help you remember vocabulary.

Yes. Esperanto present tense often covers both the simple present and the English present progressive, depending on context.

So:

• Mi subskribas la formularon kaj ricevas bibliotekkarton.

can mean:

• I sign the form and receive a library card
• I am signing the form and receiving a library card

In most real contexts, English would probably choose the progressive form: I am signing... and receiving...

Esperanto pronunciation is very regular. A rough guide:

• Mi = mee
• subskribas = soob-SKREE-bas
• la = lah
• formularon = for-moo-LAH-ron
• kaj = kai (rhymes with English eye after a k sound)
• ricevas = ree-TSEH-vas
• bibliotekkarton = bib-lee-o-tek-KAR-ton

A few useful pronunciation notes:

• j is pronounced like English y
• c is pronounced ts
• stress is always on the second-to-last syllable

So:

• sub-SKRI-bas
• for-mu-LA-ron
• ri-CE-vas
• bib-li-o-tek-KAR-ton

Yes, to a degree.

Because it says bibliotekkarton without la, it is normally understood as a library card, not the library card.

If the sentence had:

• la bibliotekkarton

that would mean the library card.

So Esperanto makes the definite/indefinite contrast only through la versus no article. There is no separate word for a/an.