A linguiça e o pão de alho estão prontos.

Because pronto here describes a temporary state: the sausage and garlic bread are ready right now.

In Portuguese, temporary conditions usually use estar, not ser.

• estão prontos = are ready
• são prontos would not be the normal way to say food is ready

A very similar pattern is:

• A carne está pronta. = The meat is ready.
• As bebidas estão geladas. = The drinks are cold.

So in this sentence, estar is the natural choice.

Because together they make a compound subject joined by e:

• A linguiça = singular
• O pão de alho = singular
• A linguiça e o pão de alho = plural as a group

So the verb has to be plural:

• A linguiça está pronta.
• O pão de alho está pronto.
• A linguiça e o pão de alho estão prontos.

This works just like English: The sausage and the garlic bread are ready, not is ready.

Because when Portuguese has a mixed-gender plural group—one feminine noun and one masculine noun—the default agreement is masculine plural.

Here:

• linguiça is feminine
• pão is masculine

So the combined group takes masculine plural:

• prontos

Compare:

• A linguiça está pronta.
• O pão de alho está pronto.
• A linguiça e o pão de alho estão prontos.

If both nouns were feminine, you would use prontas:

• A linguiça e a salada estão prontas.

They are the definite articles: a = the for a feminine singular noun, and o = the for a masculine singular noun.

So:

• a linguiça = the sausage
• o pão de alho = the garlic bread

Portuguese often uses definite articles in places where English may or may not use the. In English, you might say either:

• The sausage and the garlic bread are ready
• Sausage and garlic bread are ready

But in Portuguese, in a normal sentence about specific food being discussed, using the articles is very natural.

You usually learn noun gender together with the noun:

• a linguiça
• o pão

The article tells you the gender very clearly.

There are some patterns:

• nouns ending in -a are often feminine
• nouns ending in -o are often masculine

So linguiça being feminine and pão being masculine fits common patterns. But there are exceptions in Portuguese, so it is best to memorize nouns with their article whenever possible.

De literally often means of, but in food expressions it can mean something like with, made with, or flavored with.

So:

• pão de alho = garlic bread
• literally something like bread of garlic

This structure is very common in Portuguese food vocabulary:

• suco de laranja = orange juice
• bolo de chocolate = chocolate cake
• sorvete de morango = strawberry ice cream

So pão de alho is just the normal way to say garlic bread.

It can cover all of those ideas depending on context.

With food, estar pronto often means:

• ready
• done
• finished cooking
• ready to be served

So at a barbecue, A linguiça e o pão de alho estão prontos would usually mean the food is done and can be eaten now.

Portuguese often uses pronto in exactly this practical, everyday way.

Yes, it is possible in some contexts, but it sounds less neutral.

Without the articles, it can feel more like:

• a heading
• a menu item
• a list
• a more general statement

In ordinary speech, if you mean the specific sausage and garlic bread you are preparing or talking about, A linguiça e o pão de alho estão prontos sounds more natural.

So:

• A linguiça e o pão de alho estão prontos. = most natural in normal conversation
• Linguiça e pão de alho estão prontos. = possible, but less standard in that situation

A rough Brazilian Portuguese approximation is:

leen-GWEE-sa

A few useful details:

• lin has a nasal quality, so it is not exactly like English leen
• gui sounds like gwee
• ç sounds like s
• the stress is on gui

So the word is approximately:

lin-GUI-ça

Not a perfect English spelling, but leen-GWEE-sa is a good starting point.

They help show pronunciation.

1. The cedilla in ç

In linguiça, the ç makes an s sound:

• ça sounds like sa

So linguiça is not pronounced with a k sound at the end.

2. The tilde in ão

In estão, ão is a very common Portuguese nasal ending. It does not sound exactly like any normal English ending. A rough approximation is something like:

eh-STOW with a nasal sound at the end

The tilde tells you the vowel is nasalized.

So these marks are not decoration—they are important for pronunciation.