La bremso kaj la bremsbloko estas novaj.

Because the subject is made of two things joined by kaj: la bremso kaj la bremsbloko. In Esperanto, an adjective agrees in number with what it describes, so the predicate adjective must be plural: novaj.

Each noun itself is still singular, because each one names one item. But together they form a plural subject.

Compare:

• La bremso estas nova.
• La bremsbloko estas nova.
• La bremso kaj la bremsbloko estas novaj.

Esperanto verbs do not change for singular/plural or for person. Estas is the same with all subjects:

• mi estas
• vi estas
• li estas
• ili estas

So even with a plural subject, you still use estas. The plural is shown by the subject and by the adjective novaj, not by the verb.

La is the definite article, and it always stays la. It does not change for number, gender, or case.

Repeating la before both nouns is normal and clear: la bremso kaj la bremsbloko

This makes it explicit that both nouns are definite. In some coordinated expressions, one la can sometimes cover the whole pair, but repeating it is very common and often clearer, especially when the two nouns are separate items.

It is a compound word. Esperanto often combines roots into a single word.

Here you can think of it as:

• brems- = brake / braking
• blok- = block
• -o = noun ending

So bremsbloko is literally something like brake-block.

In Esperanto compounds, the last part usually gives the main category of the word. Since bremsbloko ends in -o, the whole word is a noun.

Esperanto very often uses a single compound word where English might use two separate words. Writing bremsbloko as one word shows that it is a single combined concept.

A two-word expression such as bremsa bloko can sometimes be possible, but the one-word compound is often the more standard or tighter way to express the idea.

Because there is no direct object here.

The -n ending is mainly used for:

• the direct object
• motion toward something in some expressions

In this sentence:

• la bremso kaj la bremsbloko is the subject
• novaj is a predicate adjective after estas

After esti (to be), the complement normally does not take -n.

These endings are part of Esperanto’s regular grammar:

• -o = noun

  • bremso
  • bremsbloko

• -a = adjective

  • nova

• -j = plural

  • novaj

So novaj is an adjective in the plural form. This is one of the most regular features of Esperanto: the endings tell you a lot about the job each word is doing.

Esperanto normally stresses the second-to-last syllable of each word:

• BREM-so
• brems-BLO-ko
• ES-tas
• NO-vaj

So the sentence is pronounced with very regular stress: La BREM-so kaj la brems-BLO-ko ES-tas NO-vaj.

Also, j is pronounced like English y, so the end of novaj has a glide sound similar to -ai / -ay.