Questo materiale è infiammabile.

Because materiale is a masculine singular noun in Italian, so the demonstrative must match it.

• questo = this (masculine singular)
• questa = this (feminine singular)

Even though materiale ends in -e, it is still masculine. In Italian, nouns ending in -e can be either masculine or feminine, so you often have to learn the gender with the word.

Examples:

• questo materiale = this material
• questa sostanza = this substance

The verb è is from essere = to be.

So the structure is:

• Questo materiale = this material
• è = is
• infiammabile = flammable

Italian often uses essere + adjective, just like English:

• Il vetro è fragile = Glass is fragile
• La porta è aperta = The door is open

So Questo materiale è infiammabile literally means This material is flammable.

The accent is important because è means is, while e without an accent means and.

So:

• è = is
• e = and

Compare:

• Questo materiale è infiammabile = This material is flammable
• legno e plastica = wood and plastic

In writing, Italians always distinguish these two.

Infiammabile is an adjective. It describes the noun materiale.

So in this sentence:

• materiale = noun
• infiammabile = adjective describing it

It works like English adjectives such as flammable, fragile, or dangerous.

Other examples:

• un liquido infiammabile = a flammable liquid
• prodotti infiammabili = flammable products

Yes, but only partly.

Infiammabile has the singular form ending in -e and the plural form ending in -i.

• masculine singular: infiammabile
• feminine singular: infiammabile
• masculine plural: infiammabili
• feminine plural: infiammabili

So the singular form is the same for masculine and feminine.

Examples:

• Questo materiale è infiammabile = This material is flammable
• Questa sostanza è infiammabile = This substance is flammable
• Questi materiali sono infiammabili = These materials are flammable
• Queste sostanze sono infiammabili = These substances are flammable

Because questo already means this, so you do not also use the.

In English, you say:

• this material

Not:

• this the material

Italian works the same way:

• questo materiale

Not:

• questo il materiale in a normal sentence like this.

So questo already determines the noun.

Normally, no. The natural and standard order here is:

• questo materiale infiammabile = this flammable material
• questo materiale è infiammabile = this material is flammable

Italian adjectives can sometimes come before the noun, but with a technical adjective like infiammabile, the normal position is after the noun.

So:

• materiale infiammabile sounds normal
• infiammabile materiale sounds unusual or stylistically marked

Yes, this is worth noticing.

In Italian, infiammabile clearly means flammable: able to catch fire easily.

It is related to the English word inflammable, which in modern English can confuse learners because many people think the prefix in- means not, but here it does not. It comes from a different origin and still means able to catch fire.

So:

• Italian infiammabile = English flammable
• Italian non infiammabile = English non-flammable

It is pronounced approximately:

een-fyam-MAH-bee-leh

A few useful points:

• in- sounds like een
• fiam- has a fyam sound
• stress falls on -ma-: infiamMAbile
• the final -e is pronounced, not silent

So unlike English, you should pronounce every syllable clearly.

Italian is simply talking about this material as one substance or type of material.

• Questo materiale è infiammabile = This material is flammable

If you wanted the plural, you would say:

• Questi materiali sono infiammabili = These materials are flammable

Italian and English do not always choose singular and plural in exactly the same situations, but here the singular is perfectly normal.

Yes, but it means something slightly different in structure.

• Questo materiale è infiammabile = This material is flammable
• Questo è un materiale infiammabile = This is a flammable material

The first sentence talks directly about the material. The second points to something first with questo = this, and then identifies it as a flammable material.

Both are correct, but they are not exactly the same sentence pattern.

You would change all the words that need plural agreement:

• questo → questi
• materiale → materiali
• è → sono
• infiammabile → infiammabili

So:

Questi materiali sono infiammabili.

This means These materials are flammable.

Yes, if you want to say that material instead of this material.

For materiale, the correct masculine singular form is:

• quel materiale = that material

So:

• Questo materiale è infiammabile = This material is flammable
• Quel materiale è infiammabile = That material is flammable

You would use quello before certain consonant combinations, but not before materiale. For example:

• quello studente = that student
• quel materiale = that material