Questo è un libro inglese.

Yes. Questo means this.

In Questo è un libro inglese, questo is being used on its own as a pronoun, so it means this one / this thing.

Compare:

• Questo è un libro inglese. = This is an English book.
• Questo libro è inglese. = This book is English.

So questo can either:

• stand alone: this
• go before a noun: this book = questo libro

Because è and e are different words in Italian.

• è = is
• e = and

So:

• Questo è un libro inglese. = This is an English book.
• pane e vino = bread and wine

The accent is very important here because it changes the meaning completely.

Because libro is a masculine singular noun that begins with a normal consonant, so it takes un.

Italian indefinite articles:

• un for most masculine singular nouns
• uno for masculine singular nouns beginning with s + consonant, z, ps, gn, and a few others
• una for feminine singular nouns

Examples:

• un libro = a book
• uno studente = a student
• uno zaino = a backpack
• una casa = a house

So libro correctly takes un.

Because in Italian, adjectives often come after the noun.

So:

• un libro inglese = an English book

This is very normal in Italian. English usually says:

• an English book

But Italian commonly says:

• a book English literally, though of course the real meaning is an English book

Some adjectives can come before the noun in Italian, but nationality adjectives like inglese normally come after it.

It can mean both, depending on context.

In this sentence, un libro inglese usually means:

• an English book
• that is, a book from England or in English, depending on the situation

Elsewhere, inglese can also mean:

• English (the language): Studio inglese. = I study English.
• English (a person/adjective): un uomo inglese = an English man

So the exact meaning comes from context.

Good question. Some Italian adjectives have the same form for masculine and feminine singular.

Inglese is one of those adjectives.

Singular:

• libro inglese = masculine singular
• rivista inglese = feminine singular

Plural:

• libri inglesi
• riviste inglesi

So inglese stays the same in the singular for both masculine and feminine, but changes to inglesi in the plural.

It would become:

• Questi sono libri inglesi. = These are English books.

Changes:

• questo → questi
• è → sono
• un libro → libri
• inglese → inglesi

So several words change to agree with the plural.

Yes, but it means something slightly different.

• Questo è un libro inglese. = This is an English book.
• Questo è inglese. = This is English.

In the second sentence, inglese describes this directly. The noun book is not stated.

So if you want to say specifically that the thing is a book, you need un libro.

Yes, and that is also correct, but the structure is different.

• Questo è un libro inglese. = This is an English book.
• Questo libro è inglese. = This book is English.

The first identifies what this is.
The second starts with this book and then says something about it.

In many situations, both are possible, but they are not exactly the same sentence pattern.

It is pronounced roughly like KWEH-stoh.

A few helpful points:

• qu in Italian sounds like kw
• the stress is on the first syllable: QUE-sto
• the final o is clearly pronounced

So not like English question, but more like KWEH-stoh.

It is pronounced roughly een-GLAY-zeh.

Notes:

• the stress is on -gle-
• the final e is pronounced
• the s in this word sounds like a z in standard pronunciation

So you should not pronounce it like the English word English. It has a clearly Italian sound: een-GLAY-zeh.

Because inglese here is an adjective describing libro, not a noun by itself.

• un libro inglese = an English book

Here, un goes with libro, and inglese simply describes the noun.

But if inglese is used as a noun, you may need an article depending on the sentence:

• L’inglese è difficile. = English is difficult.
• È un inglese. = He is an Englishman.

So in your sentence, no extra article is needed before inglese.

Use questo for this and quello for that.

• Questo è un libro inglese. = This is an English book.
• Quello è un libro inglese. = That is an English book.

Very broadly:

• questo points to something near the speaker
• quello points to something farther away

That is the basic distinction learners usually start with.