La bitlibro estas senpaga; la sonlibro kaj enciklopedio estas haveblaj.

Yes. They are regular Esperanto compounds.

In Esperanto, compound words are often written as one word, and the last part is the main idea:

• bit-libro = a kind of book connected with bits or digital form
• son-libro = a kind of book connected with sound

So both are types of libro.

A native speaker might also use other terms in real life, depending on context, but these forms are grammatically clear and easy to understand.

Senpaga is built from:

• sen = without
• pag = pay, payment
• -a = adjective ending

So literally it means without payment.

That is why it means free of charge. This is different from libera, which usually means free in the sense of not restricted or not controlled.

Haveblaj comes from:

• hav- = have
• -ebl- = able to be, possible to be
• -a = adjective
• -j = plural

So havebla literally means able to be had, which in natural English is available or obtainable.

Then haveblaj is the plural form: available for more than one thing.

Because Esperanto adjectives agree with the nouns they describe.

• La bitlibro is singular, so the adjective is singular: senpaga
• La sonlibro kaj enciklopedio refers to two things together, so the adjective is plural: haveblaj

This agreement is very regular in Esperanto.

Because they are predicate adjectives, not direct objects.

In both clauses, the structure is:

• subject + estas
  • adjective

So:

• La bitlibro estas senpaga
• La sonlibro kaj enciklopedio estas haveblaj

After estas, the adjective describes the subject, so it stays in the normal form, not the accusative.

Because one la can cover more than one noun joined by kaj.

So:

• la sonlibro kaj enciklopedio

can mean:

• the audiobook and the encyclopedia

If you want, you can also repeat the article:

• la sonlibro kaj la enciklopedio

Both are possible. The version with one la is shorter and very normal.

The semicolon separates two related independent clauses:

• La bitlibro estas senpaga
• la sonlibro kaj enciklopedio estas haveblaj

Each part could stand as its own sentence, but they are closely connected in meaning, so a semicolon works well. Esperanto punctuation here is much like English punctuation.

No, Esperanto word order is fairly flexible, but this sentence uses the most neutral and easiest order:

• subject + verb + complement

So:

• La bitlibro estas senpaga

is the plain, standard way to say it.

You could change the order for style or emphasis, but that would sound more marked. For a learner, this word order is the best one to use first.

A few useful pronunciation points:

• c is always ts
• stress is always on the second-to-last syllable

So:

• enciklopedio = en-ci-klo-pe-DI-o, with c pronounced ts
• haveblaj = ha-VE-blaj

Also, in -aj, the sound is a diphthong, roughly like the vowel sound in English eye.

So haveblaj ends with something like -blai.