Vorrei un altro bicchiere d’acqua fresca.

Vorrei is the conditional form of volere and means I would like. It sounds more polite and natural in requests.

• Vorrei un altro bicchiere d’acqua fresca. = I’d like another glass of fresh/cool water.
• Voglio un altro bicchiere d’acqua fresca. = I want another glass of fresh/cool water.

Voglio is not wrong grammatically, but it can sound too direct in many situations, especially in a restaurant or café.

Vorrei is the present conditional of volere.

The present conditional of volere is:

• io vorrei = I would like
• tu vorresti
• lui/lei vorrebbe
• noi vorremmo
• voi vorreste
• loro vorrebbero

In everyday Italian, this form is very common for polite requests.

Un altro means another or one more.

It is made of:

• un = a
• altro = other / another

So un altro bicchiere literally means another glass or one more glass.

Because un here is the indefinite article for a masculine noun, not the shortened form of uno.

• un altro bicchiere = correct
• un’altro bicchiere = incorrect

Apostrophes are used in some cases of elision, but not here.

In Italian, altro usually comes before the noun when it means another.

So you say:

• un altro bicchiere
• un’altra domanda
• un altro giorno

Putting it after the noun would sound unnatural in this meaning.

Both come from di, meaning of, but before a word starting with a vowel, Italian often uses elision:

• di acqua → d’acqua

So bicchiere d’acqua means glass of water.

This is very common and natural in Italian.

Because after a measure word like bicchiere (glass), Italian usually uses just di + noun without an article when speaking generally.

• un bicchiere d’acqua = a glass of water
• una tazza di tè = a cup of tea
• un piatto di pasta = a plate of pasta

Dell’acqua would usually mean some water, and it is less natural after bicchiere in this sentence.

Fresca agrees with acqua, which is a feminine singular noun.

• acqua fresca = fresh/cool water

Even though bicchiere is masculine, the adjective here describes the water, not the glass.

So:

• bicchiere d’acqua fresca = glass of fresh/cool water

Usually fresca means fresh or cool, not necessarily very cold.

If you want to emphasize cold, Italian often uses:

• acqua fredda = cold water

So:

• acqua fresca = fresh/cool water
• acqua fredda = cold water

In real life, the choice depends on context, but fresca often suggests pleasantly cool water.

In this sentence, native speakers understand fresca as referring to acqua.

So the meaning is:

• a glass of fresh/cool water

Not:

• a fresh/cool glass

The structure bicchiere d’acqua fresca naturally points to the water as the thing being described.

Yes, it is natural and polite.

It sounds like a customer asking for another glass of water in a courteous way.

You might also hear:

• Vorrei un altro bicchiere d’acqua, per favore.
• Potrei avere un altro bicchiere d’acqua?
• Mi porta un altro bicchiere d’acqua, per favore?

Adding per favore makes it even more polite.

A simple pronunciation guide is:

voh-RAY oon AHL-troh bee-KYEH-reh DAH-kwah FRES-kah

A few helpful notes:

• vorrei sounds roughly like voh-RAY
• gli does not appear here, so pronunciation is fairly straightforward
• ch in bicchiere sounds like a hard k
• d’acqua flows together smoothly

The stress is mainly on:

• vorREI
• ALtro
• bicCHIEre
• ACqua
• FRESca

Yes. You can simply say:

• Vorrei un altro bicchiere d’acqua.

That means I’d like another glass of water.

Adding fresca gives more detail about the kind of water you want.

You could, but it does not mean exactly the same thing.

• un altro bicchiere = another glass / one more glass
• ancora un bicchiere = one more glass / yet another glass

Both can work, but un altro bicchiere is the most direct and common way to say another glass here.

The structure is:

• Vorrei = I would like
• un altro bicchiere = another glass
• d’acqua fresca = of fresh/cool water

So the literal order is:

I would like another glass of fresh water.

Italian word order here is very similar to English, which makes this sentence fairly easy to understand once you know the vocabulary.