La pila és nova.

Because pila is a feminine singular noun in Catalan, so it takes the feminine singular definite article la.

• la pila = the battery / the pile / etc. depending on context
• masculine singular nouns usually take el

So the article has to match the noun’s gender and number.

És is the 3rd person singular present form of ser: is.

The accent matters because:

• és = is
• es = a pronoun, like himself/herself/itself in some contexts, or part of pronominal constructions

So in La pila és nova, the accent shows that this is the verb is, not the pronoun es.

Because adjectives in Catalan usually agree with the noun they describe in gender and number.

Since pila is feminine singular, the adjective must also be feminine singular:

• masculine singular: nou
• feminine singular: nova
• masculine plural: nous
• feminine plural: noves

So:

• el llibre nou = the new book
• la pila nova = the new battery

In the sentence La pila és nova, the same agreement rule applies after the verb too.

In Catalan, adjectives often come after the noun, especially when they are simply describing it.

So:

• la pila nova = the new battery

This is more normal than putting the adjective before the noun.

In your sentence, though, the adjective is not directly inside the noun phrase. It comes after the verb:

• La pila és nova = The battery is new

That is a standard sentence pattern:

• subject + verb + adjective

In this sentence, ser is used because new is being treated as a basic characteristic of the thing.

• La pila és nova = The battery is new

Catalan, like Spanish, often contrasts ser and estar. Very roughly:

• ser = what something is
• estar = how something is / is located / is in a certain state

With nou/nova, both can sometimes appear, but the meaning can shift a bit:

• és nova = it is new
• està nova = it looks/feels like new, it’s in like-new condition

So ser is the most straightforward choice here.

A careful pronunciation is approximately:

[lə ˈpilə ˈez ˈnɔβə] in Central Catalan

A rough English-friendly guide might be:

luh PEE-luh ez NAW-vuh

A few pronunciation notes:

• la is often reduced in connected speech, especially in Central Catalan
• pila has the stress on pi
• és has a clear stressed vowel
• nova has the stress on no
• the v in many Catalan varieties sounds closer to a soft b sound

Pronunciation varies somewhat by dialect.

Not if you want a complete sentence meaning The battery is new.

• La pila és nova = a full sentence
• La pila nova = a noun phrase, meaning the new battery

So:

• with és, you are making a statement
• without és, you are just naming or identifying an object

Compare:

• La pila és nova. = The battery is new.
• La pila nova és aquí. = The new battery is here.

Usually, no. In a normal sentence like this, if you mean the battery, you need the article:

• La pila és nova.

Without the article:

• Pila és nova.

that would sound ungrammatical in standard Catalan.

Catalan uses definite articles quite regularly, so English speakers often need to get used to keeping them where Catalan requires them.

The normal order here is:

• La pila = subject
• és = verb
• nova = adjective / predicate adjective

So the standard order is:

• La pila és nova.

You may sometimes see different word order for emphasis, but this is the neutral, most natural version for learners to use first.

It uses a very common pattern:

• noun phrase + ser + adjective

In other words:

• subject + to be + description

Here:

• La pila = subject
• és = is
• nova = adjective describing the subject

This is the same pattern as:

• El cotxe és vermell. = The car is red.
• La casa és gran. = The house is big.
• La pila és nova. = The battery is new.